Segment Reporting - Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019
Segment Reporting Information [Line Items]
Assets	$ 2,962,924	$ 3,004,700
Add investment balance	441,737	533,239
Great Park
Segment Reporting Information [Line Items]
Assets	1,078,574		$ 1,196,258
Add investment balance	392,769	431,835	431,835
Gateway Commercial Venture
Segment Reporting Information [Line Items]
Assets	105,388		473,398
Add investment balance	48,968	101,404	$ 101,404
Operating Segments
Segment Reporting Information [Line Items]
Assets	3,420,948	3,774,989
Other eliminations
Segment Reporting Information [Line Items]
Assets	(20,558)	(8,310)
Corporate and Unallocated
Segment Reporting Information [Line Items]
Assets	304,759	374,438
Valencia | Operating Segments
Segment Reporting Information [Line Items]
Assets	850,479	748,082
San Francisco | Operating Segments
Segment Reporting Information [Line Items]
Assets	1,221,579	1,197,081
Great Park | Operating Segments
Segment Reporting Information [Line Items]
Assets	1,243,491	1,356,417
Great Park | Removal of Results of Unconsolidated Entities
Segment Reporting Information [Line Items]
Assets	(1,078,574)	(1,196,258)
Commercial | Operating Segments
Segment Reporting Information [Line Items]
Assets	105,399	473,409
Gateway Commercial Venture | Removal of Results of Unconsolidated Entities
Segment Reporting Information [Line Items]
Assets	$ (105,388)	$ (473,398)