Discontinued Operations and Assets and Liabilities Held-for-Sale - Results from Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Cost of sales and expenses from discontinued real estate operations:
Net income from discontinued operations, net of tax	$ 0	$ (5,269)	$ 0	$ 3,053
Income (loss) on sale of discontinued operation	0	2,094	43	(9,309)
Net income (loss) from discontinued operations, net of tax	$ 0	(3,175)	43	(6,256)
Net (income) loss from discontinued operations attributable to noncontrolling interests		1,645	0	(1,150)
Net income (loss) from discontinued operations attributable to PICO Holdings, Inc.		(1,530)	43	(7,406)
Real Estate Operations
Revenue and other income from discontinued real estate operations:
Sales of real estate		39,462	0	247,213
Other		20	0	506
Total revenue and other income		39,482	0	247,719
Cost of sales and expenses from discontinued real estate operations:
Cost of real estate sold		32,221	0	200,789
General, administrative, and other		11,245	0	29,618
Sales and marketing		2,415	0	13,784
Impairment loss on long-lived assets		0	0	102
Total cost of sales and expenses		45,881	0	244,293
Income before income taxes		(6,399)	0	3,426
Provision for federal and state income taxes		1,130	0	(360)
Net income from discontinued operations, net of tax		(5,269)	0	3,066
Income (loss) on sale of discontinued operation		2,094	43	(9,311)
Agribusiness Operations
Cost of sales and expenses from discontinued real estate operations:
Net income from discontinued operations, net of tax		0	0	(13)
Income (loss) on sale of discontinued operation		$ 0	$ 0	$ 2