Reporting Segments and Related Information - Revenue Components of Real Estate Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue from External Customer [Line Items]
Equity in earnings of unconsolidated joint ventures, net	$ 1,592	$ 1,724	$ 2,411	$ 3,512
Profit from commercial/industrial and unconsolidated joint ventures	4,642	310	5,262	(3,610)
Real estate - commercial/industrial
Revenue from External Customer [Line Items]
Commercial/industrial revenues	2,445	2,432	6,788	6,704
Equity in earnings of unconsolidated joint ventures, net	1,592	1,724	2,411	3,512
Total commercial/industrial revenues and equity in earnings from unconsolidated joint ventures	4,037	4,156	9,199	10,216
Profit from commercial/industrial and unconsolidated joint ventures	2,359	2,841	4,814	5,256
Real estate - commercial/industrial | Pastoria Energy Facility
Revenue from External Customer [Line Items]
Commercial/industrial revenues	1,231	1,054	3,132	2,779
Real estate - commercial/industrial | Tejon Ranch Commerce Center
Revenue from External Customer [Line Items]
Commercial/industrial revenues	431	569	1,267	1,488
Real estate - commercial/industrial | TRCC management fees and reimbursements
Revenue from External Customer [Line Items]
Commercial/industrial revenues	212	373	612	823
Real estate - commercial/industrial | Commercial leases
Revenue from External Customer [Line Items]
Commercial/industrial revenues	178	179	523	485
Real estate - commercial/industrial | Communication leases
Revenue from External Customer [Line Items]
Commercial/industrial revenues	215	229	696	603
Real estate - commercial/industrial | Landscaping and other
Revenue from External Customer [Line Items]
Commercial/industrial revenues	178	28	558	453
Real estate - commercial/industrial | Land sale
Revenue from External Customer [Line Items]
Commercial/industrial revenues	$ 0	$ 0	$ 0	$ 73