Reporting Segments and Related Information - Revenue Components of Real Estate Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue from External Customer [Line Items]
Equity in earnings of unconsolidated joint ventures, net	$ 652	$ 1,560	$ 819	$ 1,788
Profit from commercial/industrial and unconsolidated joint ventures	(1,361)	(675)	620	(3,920)
Real estate - commercial/industrial
Revenue from External Customer [Line Items]
Commercial/industrial revenues	2,189	2,083	4,343	4,272
Equity in earnings of unconsolidated joint ventures, net	652	1,560	819	1,788
Total commercial/industrial revenues and equity in earnings from unconsolidated joint ventures	2,841	3,643	5,162	6,060
Profit from commercial/industrial and unconsolidated joint ventures	1,453	1,741	2,455	2,415
Real estate - commercial/industrial | Pastoria Energy Facility
Revenue from External Customer [Line Items]
Commercial/industrial revenues	877	881	1,901	1,725
Real estate - commercial/industrial | Tejon Ranch Commerce Center
Revenue from External Customer [Line Items]
Commercial/industrial revenues	429	392	836	919
Real estate - commercial/industrial | TRCC management fees and reimbursements
Revenue from External Customer [Line Items]
Commercial/industrial revenues	187	238	400	450
Real estate - commercial/industrial | Commercial leases
Revenue from External Customer [Line Items]
Commercial/industrial revenues	185	156	345	306
Real estate - commercial/industrial | Communication leases
Revenue from External Customer [Line Items]
Commercial/industrial revenues	297	167	481	374
Real estate - commercial/industrial | Landscaping and other
Revenue from External Customer [Line Items]
Commercial/industrial revenues	214	176	380	425
Real estate - commercial/industrial | Land sale
Revenue from External Customer [Line Items]
Commercial/industrial revenues	$ 0	$ 73	$ 0	$ 73