Revenues - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Revenue from customers	$ 24,014	$ 12,046	$ 32,947	$ 24,821
Revenues	24,307	12,387	33,527	25,460
Land sales
Disaggregation of Revenue [Line Items]
Revenue from customers	17,030	246	17,046	531
Management services
Disaggregation of Revenue [Line Items]
Revenue from customers	6,314	11,168	14,558	22,231
Operating properties
Disaggregation of Revenue [Line Items]
Revenue from customers	670	632	1,343	2,059
Operating properties leasing revenues	293	341	580	639
Revenues	963	973	1,923	2,698
Valencia
Disaggregation of Revenue [Line Items]
Revenue from customers	17,568	479
Revenues	17,861	820
Valencia | Land sales
Disaggregation of Revenue [Line Items]
Revenue from customers	17,030	24
Valencia | Management services
Disaggregation of Revenue [Line Items]
Revenue from customers	0	0
Valencia | Operating properties
Disaggregation of Revenue [Line Items]
Revenue from customers	538	455
Operating properties leasing revenues	293	341
San Francisco
Disaggregation of Revenue [Line Items]
Revenue from customers	172	972	1,147	2,065
Revenues	172	972	1,147	2,065
San Francisco | Land sales
Disaggregation of Revenue [Line Items]
Revenue from customers	0	222	0	443
San Francisco | Management services
Disaggregation of Revenue [Line Items]
Revenue from customers	40	573	835	1,271
San Francisco | Operating properties
Disaggregation of Revenue [Line Items]
Revenue from customers	132	177	312	351
Operating properties leasing revenues	0	0	0	0
Great Park
Disaggregation of Revenue [Line Items]
Revenue from customers	6,177	10,437	13,529	20,833
Revenues	6,177	10,437	13,529	20,833
Great Park | Land sales
Disaggregation of Revenue [Line Items]
Revenue from customers	0	0	0	0
Great Park | Management services
Disaggregation of Revenue [Line Items]
Revenue from customers	6,177	10,437	13,529	20,833
Great Park | Operating properties
Disaggregation of Revenue [Line Items]
Revenue from customers	0	0	0	0
Operating properties leasing revenues	0	0	0	0
Commercial
Disaggregation of Revenue [Line Items]
Revenue from customers	97	158	194	127
Revenues	97	158	194	127
Commercial | Land sales
Disaggregation of Revenue [Line Items]
Revenue from customers	0	0	0	0
Commercial | Management services
Disaggregation of Revenue [Line Items]
Revenue from customers	97	158	194	127
Commercial | Operating properties
Disaggregation of Revenue [Line Items]
Revenue from customers	0	0	0	0
Operating properties leasing revenues	$ 0	$ 0	0	0
Valencia
Disaggregation of Revenue [Line Items]
Revenue from customers			18,077	1,796
Revenues			18,657	2,435
Valencia | Land sales
Disaggregation of Revenue [Line Items]
Revenue from customers			17,046	88
Valencia | Management services
Disaggregation of Revenue [Line Items]
Revenue from customers			0	0
Valencia | Operating properties
Disaggregation of Revenue [Line Items]
Revenue from customers			1,031	1,708
Operating properties leasing revenues			$ 580	$ 639