Real Estate Investments - Preferred Equity Investments and Real Estate Under Development (Details) $ in Thousands	1 Months Ended				3 Months Ended	12 Months Ended
	Dec. 31, 2020 USD ($) property investment project unit	Sep. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Feb. 29, 2020 USD ($)	Dec. 31, 2020 USD ($) property investment project unit	Dec. 31, 2020 USD ($) property investment project unit	Dec. 31, 2019 USD ($) investment	Dec. 31, 2018 USD ($) investment
Schedule of Equity Method Investments [Line Items]
Co-investment	$ 1,018,010				$ 1,018,010	$ 1,018,010	$ 1,335,339
Ownership interests, number of consolidated projects | project	3				3	3
Ownership Interests, number of unconsolidated projects | investment	3				3	3
Number of units to be developed | unit	1,853				1,853	1,853
Real Estate Predevelopment Projects
Schedule of Equity Method Investments [Line Items]
Actual cost of active development projects						$ 948,000
Minimum
Schedule of Equity Method Investments [Line Items]
Annualized preferred return rate						9.00%	10.15%	10.25%
Maximum
Schedule of Equity Method Investments [Line Items]
Annualized preferred return rate						11.50%	11.30%	12.00%
Equity Method Investments
Schedule of Equity Method Investments [Line Items]
Commitment to fund preferred equity investment in the project						$ 191,300	$ 141,700	$ 45,100
Number of investments with a commitment to fund | investment						7	5	2
Equity method investment, funded amount	$ 55,100				$ 55,100	$ 55,100		$ 42,100
Total Preferred Interest Investments
Schedule of Equity Method Investments [Line Items]
Co-investment	502,300				502,300	$ 502,300	$ 444,900
Joint Venture That Holds Property In Los Angeles, CA
Schedule of Equity Method Investments [Line Items]
Proceeds from partial redemption of co-investment			$ 11,300		$ 10,700
Early redemption fee			$ 200
Preferred Equity Investment Property In Southern California
Schedule of Equity Method Investments [Line Items]
Proceeds from partial redemption of co-investment	$ 31,300	$ 13,400		$ 13,400
Number of properties | property	2				2	2