Segment Reporting - Revenues and Profit (loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Revenues	$ 8,377	$ 12,014	$ 41,904	$ 37,474
Profit (Loss)	36,422	(22,955)	(2,559)	7,150
Operating Segments
Segment Reporting Information [Line Items]
Revenues	13,764	59,224	87,099	294,398
Profit (Loss)	60,342	(8,897)	75,728	75,123
Corporate and Unallocated
Segment Reporting Information [Line Items]
Profit (Loss)	(12,820)	(16,090)	(39,864)	(46,957)
Valencia
Segment Reporting Information [Line Items]
Revenues	240	151	18,897	2,586
Valencia | Operating Segments
Segment Reporting Information [Line Items]
Revenues	240	151	18,897	2,586
Profit (Loss)	(3,231)	(4,892)	(6,348)	(13,237)
San Francisco
Segment Reporting Information [Line Items]
Revenues	138	950	1,285	3,015
San Francisco | Operating Segments
Segment Reporting Information [Line Items]
Revenues	138	950	1,285	3,015
Profit (Loss)	(1,829)	(3,662)	(7,387)	52,947
Great Park
Segment Reporting Information [Line Items]
Revenues	7,895	10,814	21,424	31,647
Profit (Loss)	(4,195)	(690)	(38,647)	7,258
Great Park | Operating Segments
Segment Reporting Information [Line Items]
Revenues	8,123	49,450	44,478	262,863
Profit (Loss)	(10,193)	970	(22,920)	38,913
Great Park | Removal of Results of Unconsolidated Entities
Segment Reporting Information [Line Items]
Revenues	(228)	(38,636)	(23,054)	(231,216)
Profit (Loss)	11,968	2,370	28,245	(29,205)
Commercial
Segment Reporting Information [Line Items]
Revenues	104	99	298	226
Commercial | Operating Segments
Segment Reporting Information [Line Items]
Revenues	5,263	8,673	22,439	25,934
Profit (Loss)	75,595	(1,313)	112,383	(3,500)
Gateway Commercial Venture
Segment Reporting Information [Line Items]
Profit (Loss)	56,618	(1,060)	84,064	(2,795)
Gateway Commercial Venture | Removal of Results of Unconsolidated Entities
Segment Reporting Information [Line Items]
Revenues	(5,159)	(8,574)	(22,141)	(25,708)
Profit (Loss)	$ (75,491)	$ 1,412	$ (112,085)	$ 3,726