Segment Reporting [Abstract] Revenue from External Customers by Products and Services [Table] Revenue from External Customers by Products and Services [Table] Business Segments [Axis] Segments [Axis] Segment [Domain] Segments [Domain] Ranch operations Ranch Operations [Member] Ranch Operations [Member] Revenue from External Customer [Line Items] Revenue from External Customer [Line Items] Total revenues Revenues Total expenses Costs and Expenses Operating results Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Retirement Benefits [Abstract] Summary of changes in benefit obligations and plan assets Schedule of Net Funded Status [Table Text Block] Schedule of other changes in plan assets and benefit obligations recognized in other comprehensive income Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block] Summary of amounts expected to be recognized as component of net periodic pension costs during the next fiscal year Schedule of Amounts in Accumulated Other Comprehensive Income (Loss) to be Recognized over Next Fiscal Year [Table Text Block] Schedule of expected annual benefit payments Schedule of Expected Benefit Payments [Table Text Block] Schedule of fair value of plan assets by investment type Schedule of Allocation of Plan Assets [Table Text Block] Components of net periodic pension cost Schedule of Net Benefit Costs [Table Text Block] Investments, Debt and Equity Securities [Abstract] Summary of available-for-sale securities Debt Securities, Available-for-sale [Table Text Block] Summary of maturities, at par, of marketable securities by year Investments Classified by Contractual Maturity Date [Table Text Block] Share-based Payment Arrangement [Abstract] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] 1998 Plan Stock Incentive Plan 1998 [Member] Stock incentive plan. NDSI Plan Non-Employee Director Stock Incentive Plan [Member] Non-employee director stock incentive plan. Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Stock compensation costs, expensed Share-based Payment Arrangement, Expense Stock compensation costs, capitalized Share-based Payment Arrangement, Amount Capitalized Stock compensation costs Share-based Compensation Arrangement by Share-based Payment Award, Compensation Costs Share-based Compensation Arrangement by Share-based Payment Award, Compensation Costs Quarterly Financial Information Disclosure [Abstract] Unaudited Quarterly Operating Results Quarterly Financial Information [Text Block] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Table] Commitments and Contingencies Disclosure [Table] Commitments and contingencies disclosure. Counterparty Name [Axis] Counterparty Name [Axis] Counterparty Name [Domain] Counterparty Name [Domain] DMB Pacific LLC DMB Pacific LLC [Member] DMB Pacific LLC [Member] Kern County Water Agency Kern County Water Agency [Member] Kern County Water Agency [Member] Long Lived Assets Held-for-sale by Asset Type [Axis] Long Lived Assets Held-for-sale by Asset Type [Axis] Long Lived Assets Held-for-sale, Name [Domain] Long Lived Assets Held-for-sale, Name [Domain] Transferable water Transferable Water [Member] Transferable water. Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] West CFD West Community Facilities Districts [Member] West community facilities districts. East CFD East Community Facilities Districts [Member] -- None. No documentation exists for this element. -- Standby letter of credit Standby Letters of Credit [Member] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Tejon-Castac Water District Tejon-Castac Water District [Member] Tejon-Castac Water District [Member] Litigation Status [Axis] Litigation Status [Axis] Litigation Status [Domain] Litigation Status [Domain] Settled Litigation Settled Litigation [Member] Litigation Case [Axis] Litigation Case [Axis] Litigation Case [Domain] Litigation Case [Domain] Antelope Valley Groundwater Cases Antelope Valley Groundwater Cases [Member] Antelope Valley Groundwater Cases [Member] Commitment and Contingencies Disclosure [Line Items] Commitment and Contingencies Disclosure [Line Items] Commitment and contingencies disclosure. Amount paid for water contracts Repayments of Long-term Capital Lease Obligations Contract renewal optional term Long Term Water Assets, Contract Renewal Optional Term Long Term Water Assets, Contract Renewal Optional Term Long-term water assets (Volume) Long-term Water Assets (Volume) Long-term Water Assets (Volume) Contractual obligation for future water payments Contractual Obligation Estimated future minimum annual payments Other Commitment Measurement period from entitlement achievement date Contract Termination, Incentive Fee Calculation, Measurement Period From Entitlement Achievement Date Contract Termination, Incentive Fee Calculation, Measurement Period From Entitlement Achievement Date Number of community facility districts Number of Community Facility Districts Number of Community Facility Districts Acres of land related to land liens Acres of Land Related to Land Liens Acres of land related to land liens. Bond debt sold by TRPFFA Long-term Line of Credit Additional bond debt authorized to be sold in future Debt Instrument, Face Amount Letters of credit outstanding amount Letters of Credit Outstanding, Amount Letter of credit period Letter of credit period Letter of credit period. Letter of credit renewal period Letter of Credit Renewal Period Letter of credit renewal period. Annual cost related to letter of credit Debt Issuance Costs, Net Additional reimbursement funds Additional Reimbursement Funds Additional reimbursement funds. Special taxes paid Taxes, Other Number of parties settled (more than) Loss Contingency, Number of Plaintiffs Percent of water used within the adjudication boundary Loss Contingency, Settlement, Percent of Water Use Within the Adjudication Boundary Loss Contingency, Settlement, Percent of Water Use Within the Adjudication Boundary Acres of Land Transferred Acres of Land Transferred Acres of Land Transferred Derivative Instruments and Hedging Activities Disclosure [Abstract] Schedule of Interest Rate Derivatives Schedule of Interest Rate Derivatives [Table Text Block] Real Estate [Abstract] Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Name of Property [Axis] Name of Property [Axis] Name of Property [Domain] Name of Property [Domain] Mountain Village Tejon Mountain Village Llc [Member] Tejon mountain village llc. Centennial Centennial Founders LLC [Member] Centennial Founders LLC Grapevine Grapevine [Member] Grapevine [Member] Tejon Ranch Commerce Center Tejon Ranch Commerce Center [Member] Tejon Ranch Commerce Center [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Real estate development Inventory, Real Estate, Land and Land Development Costs Real estate and improvements - held for lease, net Inventory, Real Estate, Improvements, Gross Inventory, Real Estate, Improvements, Gross Less accumulated depreciation Inventory, Real Estate, Improvements, Accumulated Depreciation Inventory, Real Estate, Improvements, Accumulated Depreciation Real estate and improvements - held for lease, net Inventory, Real Estate, Improvements Goodwill and Intangible Assets Disclosure [Abstract] Schedule of Long Lived Assets Held-for-sale [Table] Schedule of Long Lived Assets Held-for-sale [Table] AVEK Antelope Valley East Kern Water Agency [Member] Antelope valley east kern water agency. Wheeler Ridge Maricopa Water Storage District Wheeler Ridge Maricopa Water Storage District [Member] Wheeler Ridge Maricopa Water Storage District [Member] Long Lived Assets Held For Sale [Line Items] Long Lived Assets Held-for-sale [Line Items] Water held for future use Long-term Water Assets, Banked Water and Water Contract Rights [Abstract] Long-term Water Assets, Banked Water and Water Contract Rights [Abstract] AVEK water bank Long-term Water Assets, Banked Water Held at Agency Owned Water Bank (Volume) Long-term Water Assets, Banked Water Held at Agency Owned Water Bank (Volume) Company water bank Long-term Water Assets, Banked Water Held at Company Owned Water Bank (Volume) Long-term Water Assets, Banked Water Held at Company Owned Water Bank (Volume) Transferable water Long-term Water Assets, Transferrable Water (Volume) Long-term Water Assets, Transferrable Water (Volume) Total water held for future use Long-term Water Assets, Banked Water and Water Contract Rights (Volume) Long-term Water Assets, Banked Water and Water Contract Rights (Volume) Purchased water contracts Long-term Water Assets, Water Contracts (Volume) Long-term Water Assets, Water Contracts (Volume) Purchased water contracts Related Party Transaction, Long-term Water Assets, Water Contracts (Volume) Related Party Transaction, Long-term Water Assets, Water Contracts (Volume) Total purchased water contracts Long-term Water Assets, Intangible Water Contracts (Volume) Long-term Water Assets, Intangible Water Contracts (Volume) Total water held for future use and purchased water contracts Long Term Water Assets, Contracts with Company Long Term Water Assets, Contracts with Company Debt Disclosure [Abstract] Debt consists of: Long-term Debt, by Current and Noncurrent [Abstract] Notes payable Notes Payable Other borrowings Other Borrowings Total short-term and long-term debt Debt, Long-term and Short-term, Combined Amount Less line-of-credit and current maturities of long-term debt Debt, Current Less deferred loan costs Long-term debt, less current portion Long-term Debt, Excluding Current Maturities Accounting Policies [Abstract] Principles of Consolidation Consolidation, Policy [Policy Text Block] Cash Equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Marketable Securities Marketable Securities, Policy [Policy Text Block] Investments in Unconsolidated Joint Ventures Equity Method Investments [Policy Text Block] Fair Values of Financial Instruments Fair Value of Financial Instruments, Policy [Policy Text Block] Interest Rate Swap Agreements Derivatives, Policy [Policy Text Block] Variable Interest Entity Consolidation, Variable Interest Entity, Policy [Policy Text Block] Credit Risk Concentration Risk, Credit Risk, Policy [Policy Text Block] Farm Inventories Inventory, Policy [Policy Text Block] Property and Equipment Property, Plant and Equipment, Policy [Policy Text Block] Long-Term Water Assets Long-term Water Assets [Policy Text Block] Long-term Water Assets [Policy Text Block] Vineyards and Orchards Agriculture, Policy [Policy Text Block] Common Stock Options and Grants Share-based Payment Arrangement [Policy Text Block] Long-Lived Assets Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block] Revenue Recognition Revenue from Contract with Customer [Policy Text Block] Environmental Expenditures Environmental Costs, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Retirement Plan Type [Axis] Retirement Plan Type [Axis] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Pension plan Pension Plan [Member] SERP Supplemental Employee Retirement Plan [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Expected annual benefit payments based on actuarial estimates: Defined Benefit Plan, Expected Future Benefit Payment [Abstract] 2020 Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months 2021 Defined Benefit Plan, Expected Future Benefit Payment, Year Two 2022 Defined Benefit Plan, Expected Future Benefit Payment, Year Three 2023 Defined Benefit Plan, Expected Future Benefit Payment, Year Four 2024 Defined Benefit Plan, Expected Future Benefit Payment, Year Five Thereafter Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter Statement of Cash Flows [Abstract] Cash and Cash Equivalents, Period Increase (Decrease) [Abstract] Cash and Cash Equivalents, Period Increase (Decrease) [Abstract] Operating Activities Net Cash Provided by (Used in) Operating Activities [Abstract] Net income (loss) Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Adjustments to reconcile net income (loss) to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization Amortization of premium/discount of marketable securities Accretion (Amortization) of Discounts and Premiums, Investments Equity in earnings of unconsolidated joint ventures, net Income (Loss) from Equity Method Investments Non-cash retirement plan expense Pension and Other Postretirement Benefits Cost (Reversal of Cost) Loss on sale of real estate/assets Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property Non-cash profits recognized from land contribution Gain (Loss) on Disposition of Other Assets Deferred income taxes Deferred Income Taxes and Tax Credits Stock compensation expense Share-based Payment Arrangement, Noncash Expense Excess tax benefit of stock-based compensation Deferred Tax Expense from Stock Options Exercised Abandonment expense Abandonment Expense Abandonment Expense Distribution of earnings from unconsolidated joint ventures Proceeds from Equity Method Investment, Distribution Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Receivables, inventories, prepaids and other assets, net Increase (Decrease) in Operating Assets Current liabilities, net Increase (Decrease) in Operating Liabilities Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Investing Activities Net Cash Provided by (Used in) Investing Activities [Abstract] Maturities and sales of marketable securities Proceeds from Sale and Maturity of Marketable Securities Purchases of marketable securities Payments to Acquire Marketable Securities Real estate and equipment expenditures Payments to Acquire Property, Plant, and Equipment Reimbursement proceeds from Communities Facilities District Payments for (Proceeds from) Other Investing Activities, Business Three Payments for (Proceeds from) Other Investing Activities, Business Three Investment in unconsolidated joint ventures Payments to Acquire Interest in Joint Venture Distribution of equity from unconsolidated joint ventures Proceeds from Equity Method Investment, Distribution, Return of Capital Investments in long-term water assets Payments to Acquire Other Investments Other Payments for (Proceeds from) Other Investing Activities Net cash provided by/(used) in investing activities Net Cash Provided by (Used in) Investing Activities Financing Activities Net Cash Provided by (Used in) Financing Activities [Abstract] Borrowings of line of credit Proceeds from Short-term Debt Repayments of line of credit Repayments of Short-term Debt Repayments of long-term debt Repayments of Long-term Debt Net proceeds from rights offering Proceeds from Issuance of Common Stock Taxes on vested stock grants Proceeds from (Payments for) Other Financing Activities Net cash (used in)/provided by financing activities Net Cash Provided by (Used in) Financing Activities Increase (decrease) in cash and cash equivalents Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Cash and cash equivalents at beginning of year Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash and cash equivalents at end of year Non-cash investing activities Supplemental Cash Flow Information [Abstract] Accrued capital and water expenditures included in current liabilities Change In Capital Expenditures Incurred But Not Yet Paid Change In Capital Expenditures Incurred But Not Yet Paid Contribution to unconsolidated joint venture Contribution of Property Long term deferred profit on land contribution Deferred Gain On Contribution Of Land Deferred Gain On Contribution Of Land Banked water and water for future delivery Banked Water and Water for Future Delivery [Member] Banked water and water for future delivery. Transferable water Total water held for future use at cost Tangible Water Assets, Banked Water and Water Contract Rights Tangible Water Assets, Banked Water and Water Contract Rights Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Operating Segments Operating Segments [Member] Corporate Corporate, Non-Segment [Member] Real estate - commercial/industrial Commercial and Industrial [Member] Commercial and industrial. Real estate - resort/residential Residential Real Estate [Member] Mineral resources Mineral Resources [Member] Mineral Resources [Member] Farming Farming and Agriculture [Member] Farming and agriculture. Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Information pretaining to assets of the business segments Segment Reporting Information, Additional Information [Abstract] Identifiable Assets Assets Depreciation and Amortization Capital Expenditures Capital Expenditures Capital Expenditures Schedule of Real Estate Schedule of Real Estate Properties [Table Text Block] Business segments Number of Reportable Segments Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Term Loan Medium-term Notes [Member] Promissory note Notes Payable, Other Payables [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Maturities of Long-term Debt [Abstract] Maturities of Long-term Debt [Abstract] 2020 Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months 2021 Long-term Debt, Maturities, Repayments of Principal in Year Two 2022 Long-term Debt, Maturities, Repayments of Principal in Year Three 2023 Long-term Debt, Maturities, Repayments of Principal in Year Four 2024 Long-term Debt, Maturities, Repayments of Principal in Year Five Thereafter Long-term Debt, Maturities, Repayments of Principal after Year Five Total Long-term Debt Other Liabilities Disclosure [Abstract] Other Liabilities Other Liabilities Disclosure [Text Block] Equity Method Investments and Joint Ventures [Abstract] Investment in Unconsolidated and Consolidated Joint Ventures Equity Method Investments and Joint Ventures Disclosure [Text Block] Quarterly Financial Information [Table] Quarterly Financial Information [Table] Quarterly Financial Information [Table] Reportable Segment Segment Profit (Loss) [Member] Segment Profit (Loss) [Member] Quarterly Financial Information [Line Items] Quarterly Financial Information [Line Items] [Line Items] for Quarterly Financial Information [Table] Total Revenue Revenue and Nonoperating Income Revenue and Nonoperating Income Segment Profit (Loss) Segment Profit (Loss), Excluding Equity in Earnings Segment Profit (Loss), Excluding Equity in Earnings Net Income (Loss) Net Income (Loss) attributable to Common Stockholders Net Income (Loss) Attributable to Parent Net (Loss) Income Per Share (in dollars per share) Earnings Per Share, Basic Net (Loss) Income, Per Share attributable to Common Stockholders (in dollars per share) Earnings Per Share, Diluted Inventory Disclosure [Abstract] Inventories consist of: Inventory, Net, Items Net of Reserve Alternative [Abstract] Farming inventories Agricultural Related Inventory, Net of Reserves Agricultural Related Inventory, Net of Reserves Other Other Inventory, Net of Reserves Inventories Inventory, Net Components of inventories Schedule of Inventory, Current [Table Text Block] Reconciliation of revenues, segment profits (losses) and net income (loss) Reconciliation of Revenue and Operating Profit (Loss) from Segments to Consolidated [Table Text Block] Reconciliation of Revenue and Operating Profit (Loss) from Segments to Consolidated [Table Text Block] Components of segment revenues Revenue from External Customers by Products and Services [Table Text Block] Schedule of information pertaining to assets of segments Schedule of Segment Reporting Information, by Segment [Table Text Block] Payables and Accruals [Abstract] Accrued vacation Accrued Vacation, Current Accrued paid personal leave Accrued Paid Personal Leave, Current Accrued Paid Personal Leave, Current Accrued bonus Accrued Bonuses, Current Other Other Employee-related Liabilities, Current Total Other Accrued Liabilities, Current Income Tax Disclosure [Abstract] Components of provision (benefit) for income taxes: Income Tax Expense (Benefit), Continuing Operations, by Jurisdiction [Abstract] Federal: Federal Income Tax Expense (Benefit), Continuing Operations [Abstract] Current Current Federal Tax Expense (Benefit) Deferred Deferred Federal Income Tax Expense (Benefit) Federal Federal Income Tax Expense (Benefit), Continuing Operations State: State and Local Income Tax Expense (Benefit), Continuing Operations [Abstract] Current Current State and Local Tax Expense (Benefit) Deferred Deferred State and Local Income Tax Expense (Benefit) State State and Local Income Tax Expense (Benefit), Continuing Operations Provision (benefit) for income taxes Income Tax Expense (Benefit) Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Interest Rate Swap Interest Rate Swap [Member] Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] Pension and supplemental executive retirement plan liability Liability, Pension and Other Postretirement and Postemployment Benefits, Noncurrent Interest rate swap liability Derivative Liability, Fair Value, Gross Liability Other Other Sundry Liabilities, Noncurrent Other liabilities Other Liabilities, Noncurrent Interest rate swap asset balance Derivative Asset, Fair Value, Gross Asset Number of types of awards Share Based Compensation Arrangement by Share Based Payment Award, Number of Award Types Share Based Compensation Arrangement by Share Based Payment Award, Number of Award Types Compensation cost not yet recognized Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount Weighted-average recognition period of compensation cost Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Components of provision (benefit) for income taxes Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Reconciliation of income tax expense from statutory Federal income tax rate Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Components of net deferred tax assets and liabilities Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Operating results Award Type [Axis] Award Type [Axis] Award Type [Domain] Award Type [Domain] Performance share grants Performance Shares [Member] Below threshold performance (in shares) Performance Awards Granted with Performance Conditions, Number of Shares to be Issued, Below Threshold Performance Performance Awards Granted with Performance Conditions, Number of Shares to be Issued, Below Threshold Performance Threshold performance (in shares) Performance Awards Granted with Performance Conditions, Minimum Number of Shares to be Issued, at Threshold Performance Performance Awards Granted with Performance Conditions, Minimum Number of Shares to be Issued, at Threshold Performance Target performance (in shares) Performance Awards Granted with Performance Conditions, Number of Shares to be Issued, at Target Performance Performance Awards Granted with Performance Conditions, Number of Shares to be Issued, at Target Performance Maximum performance (in shares) Performance Awards Granted with Performance Conditions, Maximum Number of Shares to be Issued, at Maximum Performance Performance Awards Granted with Performance Conditions, Maximum Number of Shares to be Issued, at Maximum Performance Related Party Transactions [Abstract] Related Party Transactions Related Party Transactions Disclosure [Text Block] Schedule of quarterly operating results Quarterly Financial Information [Table Text Block] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Line of Credit Facility [Table] Line of Credit Facility [Table] Revolving credit facility Revolving Credit Facility [Member] Promissory note Medium-term notes Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] Selected LIBOR rate Selected LIBOR Rate [Member] Selected LIBOR Rate [Member] LIBOR for a fixed rate term Fixed Term LIBOR [Member] Fixed Term LIBOR [Member] Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Long-term debt Basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Interest pay rate Derivative, Fixed Interest Rate Line of credit amount Line of Credit Facility, Current Borrowing Capacity RLC outstanding balance Long-term Debt, Gross Commitment fee percentage Line of Credit Facility, Commitment Fee Percentage Number of covenants Debt Instrument, Covenant Compliance, Number of Covenants Debt Instrument, Covenant Compliance, Number of Covenants Debt equity ratio Debt Covenant Compliance, Debt Equity Ratio Debt Covenant Compliance, Debt Equity Ratio Debt service coverage ratio Debt Covenant Compliance, Debt Service Coverage Ratio Debt Covenant Compliance, Debt Service Coverage Ratio Liquid assets Debt Covenant Compliance, Liquid Assets, Minimum Debt Covenant Compliance, Liquid Assets, Minimum Face amount Stated percentage Debt Instrument, Interest Rate, Stated Percentage Monthly principal and interest payments Debt Instrument, Periodic Payment Revenues Segment Reporting Information, Revenue for Reportable Segment [Abstract] Segment revenues Equity in earnings (losses) Investment income Investment Income, Net Total revenues and other income Revenue and Other Income Revenue and Other Income Segment Profits (Losses) Segment Reporting Information, Income (Loss) before Income Taxes [Abstract] Segment profits Operating Income (Loss) Other loss Other Nonoperating Expense Costs and expenses Income (loss) before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Interest cost Defined Benefit Plan, Interest Cost Net amortization and other Defined Benefit Plan, Amortization of Gain (Loss) Total net periodic pension earnings/(cost) Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Total Stockholders' Equity Parent [Member] Common Stock Common Stock [Member] Additional Paid-In Capital Additional Paid-in Capital [Member] Accumulated Other Comprehensive Loss AOCI Attributable to Parent [Member] Retained Earnings Retained Earnings [Member] Noncontrolling Interest Noncontrolling Interest [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Beginning Balance, value Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Beginning Balance (in shares) Shares, Outstanding Net income (loss) Other comprehensive income Other Comprehensive Income (Loss), Net of Tax Restricted stock issuance Stock Issued During Period, Value, Restricted Stock Award, Gross Restricted stock issuance (in shares) Stock Issued During Period, Shares, Restricted Stock Award, Gross Stock compensation APIC, Share-based Payment Arrangement, Increase for Cost Recognition Shares withheld for taxes and tax benefit of vested shares Share-based Payment Arrangement, Decrease for Tax Withholding Obligation Shares withheld for taxes and tax benefit of vested shares (in shares) Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation Rights offering, net Stock Issued During Period, Value, New Issues Rights offering, net (in shares) Stock Issued During Period, Shares, New Issues Rights offering, net Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs Centennial redemption of withdrawing member interest Adjustments to Additional Paid in Capital, Stock Issued, Modified Share-based Awards Adjustments to Additional Paid in Capital, Stock Issued, Modified Share-based Awards Ending Balance, value Ending Balance (in shares) Schedule of water revenues and cost of sales Schedule of Water Revenues and Cost of Sales [Table Text Block] Schedule of Water Revenues and Cost of Sales [Table Text Block] Tangible water assets Tangible Water Assets [Table Text Block] Tangible Water Assets [Table Text Block] Schedule of finite-lived intangible assets Schedule of Finite-Lived Intangible Assets [Table Text Block] Components of water assets Disclosure of Long Lived Assets Held-for-sale [Table Text Block] Real Estate Real Estate Disclosure [Text Block] Stockholders' Equity Note [Abstract] Weighted Average Number of Shares Outstanding, Diluted [Abstract] Weighted Average Number of Shares Outstanding, Diluted [Abstract] Common stock (in shares) Weighted Average Number of Shares Outstanding, Basic Common stock equivalents-stock options, grants (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Diluted shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Diluted Commercial revenues Equity in earnings of unconsolidated joint ventures Commercial revenues and equity in earnings of unconsolidated joint ventures Revenues and Income (Loss) from Equity Method Investments Revenues and Income (Loss) from Equity Method Investments Commercial expenses Operating results from commercial and unconsolidated joint ventures Schedule of Revenues from External Customers and Long-Lived Assets [Table] Schedule of Revenues from External Customers and Long-Lived Assets [Table] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] Los Angeles, California Los Angeles, California [Member] Los Angeles, California [Member] Bakersfield, California Bakersfield, California [Member] Bakersfield, California [Member] Revenues from External Customers and Long-Lived Assets [Line Items] Revenues from External Customers and Long-Lived Assets [Line Items] Area of land Area of Land Distance from city Property Border, Distance to Major City Property Border, Distance to Major City Number of joint ventures Variable Interest Entity, Number of Entities Consolidated Variable Interest Entity, Number of Entities Consolidated Long-Term Water Assets Long Lived Assets Held for Sale or Future Use [Text Block] Long lived assets held for sale or future use. SWP contracts State Water Project Contracts [Member] State water project contracts. PEF Pastoria Energy Facility, LLC [Member] Pastoria Energy Facility, LLC [Member] Statistical Measurement [Axis] Statistical Measurement [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] Maximum Maximum [Member] Consolidated Entities [Axis] Consolidated Entities [Axis] Consolidated Entities [Domain] Consolidated Entities [Domain] Ranchcorp Subsidiaries [Member] AVEK water bank (in acre-feet) AVEK water for future delivery (in acre-feet) Long-term Water Assets, Water Contract Rights for Future Delivery (Volume) Long-term Water Assets, Water Contract Rights for Future Delivery (Volume) Long-term water assets (Volume) (in acre-feet) Consumer price per acre (per acre-foot) Cost of Purchased Water, Area Cost of Purchased Water, Area Annual fee increase, percent Long Term Water Assets, Purchased, Annual Fee Increase, Percent Long Term Water Assets, Purchased, Annual Fee Increase, Percent Water assets, volume available for purchase from 2017-2030 (up to) (in acre-feet) Long-term Water Assets (Volume), Amount After Year One Long-term Water Assets (Volume), Amount After Year One Annual option payment, percent Long Term Water Assets, Purchased, Annual Option Payment, Percent Long Term Water Assets, Purchased, Annual Option Payment, Percent Cost components: Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] Service cost Defined Benefit Plan, Service Cost Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Net amortization and deferral Settlement recognition Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement Leases [Abstract] Leases Lessor, Operating Leases [Text Block] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Financial Instrument [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] Certificates of deposit Certificates of Deposit [Member] U.S. Treasury and agency notes US Treasury and Government Short-term Debt Securities [Member] Corporate notes Corporate Note Securities [Member] Municipal notes Municipal Bonds [Member] Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-sale [Line Items] Summary of maturities, at par, of marketable securities Available for Sale Securities, Fiscal Year Maturity [Abstract] Available for sale securities, fiscal year maturity. 2019 Debt Securities, Available for Sale Securities Maturities Year One at Par Debt Securities, Available for sale securities maturities, year one, at par. 2020 Debt Securities, Available for Sale Securities Maturities, Year Two, at Par Debt Securities, Available for sale securities maturities, year two, at par. 2021 Debt Securities, Available for Sale Securities Maturities, Year Three, at Par Debt Securities, Available for sale securities maturities, year three, at par. Total Debt Securities, Available for Sale Securities Maturities at Par Debt Securities, Available for sale securities maturities, at par. Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Vineyards and orchards Vineyards and Orchards [Member] Vineyards and Orchards [Member] Machinery, furniture fixtures and other equipment Other Machinery and Equipment [Member] Buildings and improvements Building and Building Improvements [Member] Land and land improvements Land and Land Improvements [Member] Development in process Construction in Progress [Member] Minimum Minimum [Member] Property and equipment useful life Property, Plant and Equipment, Useful Life Property and equipment, gross Property, Plant and Equipment, Gross Less: accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Property and equipment, net Property, Plant and Equipment, Net Line of Credit and Long-term Debt Debt Disclosure [Text Block] Components of debt Schedule of Debt [Table Text Block] Summary of outstanding indebtedness and respective principal maturities Schedule of Maturities of Long-term Debt [Table Text Block] Retirement Plans Pension and Other Postretirement Benefits Disclosure [Text Block] Other Liabilities Other Liabilities [Table Text Block] Summary of income from commercial rents included in real estate revenue Schedule of Rent Income [Table Text Block] Schedule of Rent Income [Table Text Block] Schedule of future minimum rental income Lessor, Operating Lease, Payments to be Received, Maturity [Table Text Block] Schedule of Equity Method Investments [Table] Schedule of Equity Method Investments [Table] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Petro Travel Plaza Holdings, LLC Petro Travel Holdings Llc Plaza [Member] Petro travel holdings llc plaza. Five West Parcel, LLC Five West Parcel Llc [Member] Five west parcel llc. 18-19 West, LLC Eighteen Nineteen West Llc [Member] Eighteen nineteen west llc. TRCC/Rock Outlet Center, LLC TRCC/Rock Outlet Center [Member] TRCC/Rock Outlet Center [Member] TRC-MRC 1, LLC TRC-MRC 1 LLC [Member] TRC-MRC 1 LLC [Member] TRC-MRC 2, LLC TRC-MRC 2 LLC [Member] TRC-MRC 2 LLC [Member] TRC-MRC 3, LLC TRC-MRC 3 LLC [Member] TRC-MRC 3 LLC [Member] Centennial Founders, LLC Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Balance Sheet Information Equity Method Investment, Summarized Financial Information [Abstract] Assets Equity Method Investment, Summarized Financial Information, Assets Borrowings Equity Method Investment Summarized Financial Information, Borrowings Equity Method Investment Summarized Financial Information, Borrowings Equity Equity Method Investment Summarized Financial Information, Equity Investment In Equity Method Investment Summarized Financial Information, Investment Equity Method Investment Summarized Financial Information, Investment Statement of Operations Equity Method Investment, Summarized Financial Information, Income Statement [Abstract] Revenues Equity Method Investment, Summarized Financial Information, Revenue Earnings(Loss) Equity Method Investment, Summarized Financial Information, Gross Profit (Loss) Equity in Earnings (Loss) Equity Method Investment Summarized Financial Information, Equity In Earnings (Loss) Equity Method Investment Summarized Financial Information, Equity In Earnings (Loss) Non-cash tenant allowance amortization Equity Method Investment, Summarized Financial Information, Tenant Allowance Amortization Equity Method Investment, Summarized Financial Information, Tenant Allowance Amortization Non-cash amortization of purchase accounting adjustments related to in-place leases Finite-Lived Intangible Asset, Acquired-in-Place Leases Document and Entity Information [Abstract] Document and entity information. Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Document Type Document Type Document Period End Date Document Period End Date Amendment Flag Amendment Flag Entity Emerging Growth Company Entity Emerging Growth Company Entity Small Business Entity Small Business Entity Shell Company Entity Shell Company Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Entity Common Stock Shares Outstanding Entity Common Stock, Shares Outstanding Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Current Reporting Status Entity Current Reporting Status Entity Voluntary Filers Entity Voluntary Filers Entity Public Float Entity Public Float Funded status: Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract] Change in benefit obligation - Pension Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] Benefit obligation at beginning of year Defined Benefit Plan, Benefit Obligation Service cost Interest cost Actuarial (gain)/assumption changes Defined Benefit Plan, Actuarial Gain (Loss) and Other Changes Defined Benefit Plan, Actuarial Gain (Loss) and Other Changes Benefits paid Defined Benefit Plan, Benefit Obligation, Benefits Paid Curtailments Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Curtailment Settlements paid Defined Benefit Plan, Benefit Obligation, Payment for Settlement Benefit obligation and accumulated benefit obligation at end of year Accumulated benefit obligation at end of year Defined Benefit Plan, Accumulated Benefit Obligation Change in Plan Assets Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] Fair value of plan assets at beginning of year Defined Benefit Plan, Plan Assets, Amount Actual return on plan assets Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss) Employer contribution Defined Benefit Plan, Plan Assets, Contributions by Employer Benefits/expenses paid Defined Benefit Plan, Plan Assets, Benefits Paid Fair value of plan assets at end of year Funded status - liability Defined Benefit Plan, Funded (Unfunded) Status of Plan Amounts recorded in stockholders’ equity Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract] Net actuarial loss Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax Total amount recorded Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax Amount recorded, net taxes Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax Rights offering, net (in shares) Sale of Stock, Number of Shares Issued in Transaction Exercise price (in dollars per share) Sale of Stock, Price Per Share Stock Compensation - Restricted Stock and Performance Share Grants Stock Compensation Restricted Stock and Performance Share Grants [Text Block] Stock compensation restricted stock and performance share grants. Interest Rate Swap Derivative Instruments and Hedging Activities Disclosure [Text Block] Other changes in plan assets and benefit obligations recognized in other comprehensive income: Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract] Net loss (gain) Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, before Tax Recognition of net actuarial gain or (loss) Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax Total changes Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax Changes, net of taxes Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax Inventories Inventory Disclosure [Text Block] Acre-Feet Sold (in acre-feet) Long Term Water Assets, Water Sold (Volume) Long Term Water Assets, Water Sold (Volume) Revenues Revenue from Purchased Water Revenue from Purchased Water Cost of sales Cost of Purchased Water Profit Gross Profit from Purchased Water Gross Profit from Purchased Water Reporting Segments and Related Information Segment Reporting Disclosure [Text Block] Liabilities for environmental costs Accrual for Environmental Loss Contingencies Income Statement [Abstract] Segment [Domain] Farming Revenues: Revenues [Abstract] Costs and expenses: Costs and Expenses [Abstract] Operating (loss) income Other (loss) income: Nonoperating Income (Expense) [Abstract] Other loss Total other (loss) income Nonoperating Income (Expense) (Loss) income from operations before equity in earnings of unconsolidated joint ventures Equity in earnings of unconsolidated joint ventures, net Income tax expense (benefit) Net income (loss) Net loss attributable to non-controlling interest Net Income (Loss) Attributable to Noncontrolling Interest Net income (loss) attributable to common stockholders Net income (loss) per share attributable to common stockholders, basic (in dollars per share) Net income (loss) per share attributable to common stockholders, diluted (in dollars per share) Condensed statements of operations and balance sheet information of consolidated and unconsolidated joint ventures Schedule of Condensed Income Statement and Balance Sheet Related to Joint Ventures [Table Text Block] Schedule of condensed income statement and balance sheet related to joint ventures. Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Contract-based intangible assets Contract-Based Intangible Assets [Member] Dudley-Ridge water rights Dudley Ridge Water Rights [Member] Dudley Ridge Water Rights [Member] Nickel water rights Nickel Water Rights [Member] Nickel Water Rights [Member] Tulare Lake Basin water rights Tulare Lake Basin Water Rights [Member] Tulare Lake Basin Water Rights [Member] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Costs Finite-Lived Intangible Assets, Gross Accumulated Depreciation Finite-Lived Intangible Assets, Accumulated Amortization Net cost of purchased water contracts Finite-Lived Intangible Assets, Net Total cost water held for future use Net investment in water assets Long Term Assets Held for Future Use or Sale Long term assets held for future use or sale. Statement of Financial Position [Abstract] ASSETS Assets [Abstract] Current Assets: Assets, Current [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Marketable securities - available-for-sale Debt Securities, Available-for-sale, Current Accounts receivable Accounts Receivable, after Allowance for Credit Loss, Current Inventories Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Total current assets Assets, Current Real estate and improvements - held for lease, net Real estate development (includes $104,491 at December 31, 2019 and $100,311 at December 31, 2018, attributable to Centennial Founders, LLC, Note 17) Property and equipment, net Investments in unconsolidated joint ventures Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Net investment in water assets Deferred tax assets Deferred Income Tax Assets, Net Other assets Other Assets, Noncurrent TOTAL ASSETS LIABILITIES AND EQUITY Liabilities and Equity [Abstract] Current Liabilities: Liabilities, Current [Abstract] Trade accounts payable Accounts Payable, Current Accrued liabilities and other Deferred income Contract with Customer, Liability, Current Current maturities of long-term debt Long-term Debt, Current Maturities Total current liabilities Liabilities, Current Long-term deferred gains Contract with Customer, Liability, Noncurrent Other liabilities Total liabilities Liabilities Commitments and contingencies Commitments and Contingencies Equity: Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Tejon Ranch Co. Stockholders’ Equity Stockholders' Equity Attributable to Parent [Abstract] Issued and outstanding shares - 26,096,797 at December 31, 2019 and 25,972,080 at December 31, 2018 Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital, Common Stock Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Retained earnings Retained Earnings (Accumulated Deficit) Total Tejon Ranch Co. Stockholders’ Equity Stockholders' Equity Attributable to Parent Non-controlling interest Stockholders' Equity Attributable to Noncontrolling Interest Total equity TOTAL LIABILITIES AND EQUITY Liabilities and Equity Defined Benefit Plan, Plan Assets, Category [Axis] Defined Benefit Plan, Plan Assets, Category [Axis] Defined Benefit Plan, Plan Assets, Category [Domain] Defined Benefit Plan, Plan Assets, Category [Domain] Equities Defined Benefit Plan, Equity Securities [Member] Debt Defined Benefit Plan, Debt Security [Member] Money market funds Money Market Funds [Member] Average service period Defined Benefit Plan, Average Service Period Defined Benefit Plan, Average Service Period Comprehensive loss position Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment and Tax Estimated contribution to the pension plan Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year Current investment policy targets: Defined Benefit Plan, Plan Assets, Allocations [Abstract] Current investment mix Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage Assumptions used in determining periodic pension cost: Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] Rate of increase in periodic pension costs Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase Expected long-term rate of return on plan assets Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets Assumptions used in determining actuarial present value of projected benefits obligation: Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract] Weighted-average discount rate Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate Rate of increase in future compensation levels Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase TRCC-East TRCC-East [Member] TRCC-East [Member] Land Land [Member] Number of acres for development Development of Building Development of building. Transaction costs Contribution of Property, Transaction Costs Contribution of Property, Transaction Costs Gross profit Gross Profit Deferred gain on sale Equity Method Investment, Deferred Gain on Sale Statement of Comprehensive Income [Abstract] Comprehensive income attributable to common stockholders Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Other comprehensive income: Other Comprehensive Income (Loss), Net of Tax [Abstract] Unrealized gain (loss) on available-for-sale securities Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Tax Benefit plan adjustments Unrealized interest rate swap gains Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, before Tax Unrealized interest rate swap gains Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax Other comprehensive (loss) income before taxes Other Comprehensive Income (Loss), before Tax Benefit (provision) for income taxes related to other comprehensive income items Other Comprehensive Income (Loss), Tax Other comprehensive (loss) income Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Comprehensive loss attributable to non-controlling interests Comprehensive income (loss) attributable to common stockholders Comprehensive Income (Loss), Net of Tax, Attributable to Parent Vineyards and Other Farming Related Assets Vineyards and Other Farming Related Assets [Member] Vineyards and Other Farming Related Assets [Member] Segments [Axis] Segments [Domain] Farming and Agriculture Product and Service [Axis] Product and Service [Axis] Product and Service [Domain] Product and Service [Domain] Almonds Almonds [Member] Almonds [Member] Pistachios Pistachios [Member] Pistachios [Member] Acres of vineyards abandoned Acres of Abandoned Vineyards Acres of Abandoned Vineyards Net book value related to vineyards and other farming related assets Farming revenue adjustments for differences between original estimates and actual revenues received Farming Revenue, Adjustment to Final Settlement Price Farming Revenue, Adjustment to Final Settlement Price New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Accounting Standards Update 2016-02 Accounting Standards Update 2016-02 [Member] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Operating lease term Lessee, Operating Lease, Term of Contract Operating lease right-of-use asset Operating Lease, Right-of-Use Asset Operating Lease, Liability Operating Lease, Liability Discount rate for future annual cash lease payments Lessee, Operating Lease, Discount Rate Equity Stockholders' Equity Note Disclosure [Text Block] Components of deferred tax assets and liabilities: Components of Deferred Tax Assets and Liabilities [Abstract] Deferred income tax assets: Deferred Tax Assets, Gross [Abstract] Accrued expenses Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Accrued Liabilities Deferred revenues Deferred Tax Assets, Deferred Income Capitalization of costs Deferred Tax Assets, Deferred Expense, Capitalized Costs Deferred Tax Assets, Deferred Expense, Capitalized Costs Pension adjustment Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Pensions Stock grant expense Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost State deferred taxes Deferred Tax Assets, State Taxes Book deferred gains Deferred Tax Assets, Book Deferred Gains Deferred Tax Assets, Book Deferred Gains Joint venture allocations Deferred Tax Assets, Equity Method Investments Provision for additional capitalized costs Deferred Tax Assets, Deferred Expense, Provision for Additional Capitalized Costs Deferred Tax Assets, Deferred Expense, Provision for Additional Capitalized Costs Interest rate swap Deferred Tax Assets, Derivative Instruments Other Deferred Tax Assets, Other Total deferred income tax assets Deferred Tax Assets, Gross Deferred income tax liabilities: Deferred Tax Liabilities, Gross [Abstract] Deferred gains Deferred Tax Liabilities, Tax Deferred Income Depreciation Deferred Tax Liabilities, Property, Plant and Equipment Cost of sales allocations Deferred Tax Liabilities, Cost of Sales Allocations Deferred Tax Liabilities, Cost of Sales Allocations Joint venture allocations Deferred Tax Liabilities, Investment in Noncontrolled Affiliates Straight line rent Deferred Tax Liabilities, Straight Line Rent Deferred Tax Liabilities, Straight Line Rent Prepaid expenses Deferred Tax Liabilities, Prepaid Expenses State deferred taxes Deferred Tax Liabilities, State Taxes Deferred Tax Liabilities, State Taxes Interest rate swap Deferred Tax Liabilities, Derivatives Other Deferred Tax Liabilities, Other Total deferred income tax liabilities Deferred Tax Liabilities, Gross Net deferred income tax asset Deferred Tax Assets (Liabilities), Gross Deferred Tax Assets (Liabilities), Gross Allowance for deferred tax assets Deferred Tax Assets, Valuation Allowance Net deferred taxes Deferred Tax Assets, Net Marketable Securities Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Schedule of accrued liabilities Schedule of Accrued Liabilities [Table Text Block] Cash and Cash Equivalents Defined Benefit Plan, Cash and Cash Equivalents [Member] Collective Funds Equity Funds [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Level 1 Fair Value, Inputs, Level 1 [Member] Level 2 Fair Value, Inputs, Level 2 [Member] Fair value of plan assets Schedule of weighted average number of shares outstanding Schedule of Weighted Average Number of Shares [Table Text Block] Stock Grants Restricted Stock and Performance Shares [Member] Stock grants for restricted stock and performance shares. Summary of stock grant activity: Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Stock grants outstanding beginning of the year at target achievement (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number New stock grants/additional shares due to achievement in excess of target (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Vested grants (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Expired/forfeited grants (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Stock grants outstanding at target achievement (in shares) Majestic Realty Co. Majestic Realty Co. [Member] Majestic Realty Co. [Member] Rockefeller Joint Ventures Rockefeller Joint Ventures [Member] Rockefeller joint ventures. Building Improvements Building Improvements [Member] Ownership [Axis] Ownership [Axis] Ownership [Domain] Ownership [Domain] Unconsolidated joint ventures, voting rights Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage Ownership percentage Equity Method Investment, Ownership Percentage Investment in unconsolidated joint ventures Equity Method Investments Area of Real Estate Property Area of Real Estate Property Contribution of property Equity method investment Number of joint venture contracts Number of Joint Venture Contracts Number of joint venture contracts. Percentage of rentable space occupied Joint Venture, Percentage of Rentable Space Occupied Joint Venture, Percentage of Rentable Space Occupied Borrowings Area of building owned and leased Lease of Building Lease of building. Excess distributions resulting in deficit balance Distributions in Excess of Investment in Unconsolidated Joint Venture Distributions in Excess of Investment in Unconsolidated Joint Venture Borrowings under joint venture Equity Method Investment Summarized Financial Information, Line of Credit Facility, Maximum Borrowing Capacity Equity Method Investment Summarized Financial Information, Line of Credit Facility, Maximum Borrowing Capacity Purchase of assets Proceeds from Sale of Building to Third Party Proceeds from Sale of Building to Third Party Gain (Loss) on sale of properties Gain (Loss) on Disposition of Assets Number of acres for development Contribution for Joint Venture for Future Development Contribution for joint venture for future development. Construction loan percent of costs Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures, Construction Loan Costs, Percent Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures, Construction Loan Costs, Percent Equity contributions Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures, Equity Contributions, Percent Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures, Equity Contributions, Percent Number of members Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures, Number of Members Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures, Number of Members Reduction of noncontrolling interest in joint venture Noncontrolling Interest in Joint Ventures Consolidated joint venture, ownership interest Noncontrolling Interest, Ownership Percentage by Parent Property and equipment and their respective useful lives Property, Plant and Equipment [Table Text Block] U.S. tax reform adjustment Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount Income tax payments Income Taxes Paid Federal tax refunds received Proceeds from Income Tax Refunds Difference between total income tax expense and the amount computed by applying the statutory Federal income tax rate to income before taxes: Effective Income Tax Rate Reconciliation, Amount [Abstract] Income tax at statutory rate Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount State income taxes, net of Federal benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Oil and mineral depletion Effective Income Tax Rate Reconciliation, Nondeductible Expense, Depletion, Amount Permanent differences Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount Excess stock compensation expense Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Payment Arrangement, Amount U.S. Tax Reform adjustment Other Effective Income Tax Rate Reconciliation, Other Adjustments, Amount Effective tax rate Effective Income Tax Rate Reconciliation, Percent Concentration Risk [Table] Concentration Risk [Table] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Customer concentration risk Customer Concentration Risk [Member] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Revenue Revenue from Contract with Customer Benchmark [Member] Major Customers [Axis] Customer [Axis] Name of Major Customer [Domain] Customer [Domain] Pastoria Energy Facility, LLC Concentration Risk [Line Items] Concentration Risk [Line Items] Percentage of revenue Concentration Risk, Percentage Amounts expected to be recognized as component of net periodic pension costs during the next fiscal year: Defined Benefit Plan, Expected Amortization, Next Fiscal Year [Abstract] Expected return on plan assets Defined Benefit Plan, Expected Return on Plan Assets, Next Fiscal Year Defined Benefit Plan, Expected Return on Plan Assets, Next Fiscal Year Interest cost Defined Benefit Plan, Expected Interest Cost, Next Fiscal Year Defined Benefit Plan, Expected Interest Cost, Next Fiscal Year Amortization of net gain/(loss) Defined Benefit Plan, Expected Amortization of Gain (Loss), Next Fiscal Year Net periodic pension benefit/(cost) Defined Benefit Plan, Expected Net Period Benefit Cost (Credit), Next Fiscal Year Defined Benefit Plan, Expected Net Period Benefit Cost (Credit), Next Fiscal Year Fair market value of investment securities exceeds cost basis Debt Securities, Available for Sale Securities, Fair Market Value Exceeds Cost Basis, by Amount Debt Securities, Available for sale securities, fair market value exceeds cost basis, by amount. Gross unrealized holding gains Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax Gross unrealized holding losses Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax Securities, Available-for-Sale Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, after Tax Estimated taxes of change in value of available-for-sale securities Other Comprehensive Income (Loss), Securities, Available-for-sale, Tax Debt Securities, Available-for-sale [Table] Debt Securities, Available-for-sale [Table] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Cost Reported Value Measurement [Member] Estimated Fair Value Estimate of Fair Value Measurement [Member] Level 1 Marketable Securities with unrecognized losses for less than 12 months Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Marketable Securities with unrecognized losses for more than 12 months Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Marketable Securities with unrecognized gains Total Available-for-sale Securities Debt Securities, Available-for-sale Accrued Liabilities and Other Accounts Payable and Accrued Liabilities Disclosure [Text Block] Property Subject to or Available for Operating Lease, by Major Property Class [Table] Property Subject to or Available for Operating Lease, by Major Property Class [Table] Property Subject to or Available for Operating Lease [Line Items] Property Subject to or Available for Operating Lease [Line Items] Commercial lease agreements, contract terms Lessor, Operating Lease, Term of Contract Summary of income from commercial rents included in real estate revenue: Operating Leases, Income Statement, Lease Revenue [Abstract] Base rent Operating Lease, Lease Income Percentage rent Operating Lease, Lease Income, Percentage Rent Operating Lease, Lease Income, Percentage Rent Future minimum rental income on commercial, communication and right-of-way leases: Operating Leases, Future Minimum Payments Receivable [Abstract] 2020 Lessor, Operating Lease, Payments to be Received, Next Twelve Months 2021 Lessor, Operating Lease, Payments to be Received, Two Years 2022 Lessor, Operating Lease, Payments to be Received, Three Years 2023 Lessor, Operating Lease, Payments to be Received, Four Years 2024 Lessor, Operating Lease, Payments to be Received, Five Years Thereafter Lessor, Operating Lease, Payments to be Received, Thereafter Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Other Liabilities Other Liabilities [Member] Other Assets Other Assets [Member] Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Weighted Average Interest Pay Rate Fair Value Derivative Liability Fair Value Derivative Asset Notional Amount Derivative, Notional Amount Income Taxes Income Tax Disclosure [Text Block] Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Related Party Transaction [Axis] Related Party Transaction [Axis] Related Party Transaction [Domain] Related Party Transaction [Domain] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Executive Vice President and Chief Operating Officer Management [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Acres of land Related Party Transaction, Area of Land Related Party Transaction, Area of Land Water contracts and related costs Related Party Transaction, Amounts of Transaction Summary of performance share grants with performance conditions Schedule of Share-based Payment Award, Performance Share Awards Granted, by Performance Conditions [Table Text Block] Schedule of Share-based Payment Award, Performance Share Awards Granted, by Performance Conditions [Table Text Block] Summary of stock grant activity Schedule of Nonvested Share Activity [Table Text Block] Summary of stock compensation costs for employee and NDSI plans Share-based Payment Arrangement, Cost by Plan [Table Text Block] Common stock, par value per share (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock, authorized shares (in shares) Common Stock, Shares Authorized Common stock, issued shares (in shares) Common Stock, Shares, Issued Common stock, outstanding shares (in shares) Common Stock, Shares, Outstanding Real estate development