Real Estate - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) Building	Dec. 31, 2017 USD ($)
Net gain on sales of real estate properties	$ 447,637	$ 256,810	$ 157,057
Net gain on sales of unconsolidated entities	69,500
Net gain on sales of land parcels	$ 2,044	987	19,167
Non-cash asset impairment charge		$ 702	$ 1,693
San Francisco [Member]
Number of buildings damaged due to fire | Building		1