Co-investments - Combined Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Equity Method Investment, Summarized Financial Information, Assets [Abstract]
Rental properties and real estate under development	$ 435,865		$ 546,075
Other liabilities	41,290		36,565
Equity Method Investment, Summarized Financial Information, Income Statement [Abstract]
Interest expense	(55,147)	$ (53,643)
General and administrative	(13,982)	(13,459)
Total co-investment
Equity Method Investment, Summarized Financial Information, Assets [Abstract]
Rental properties and real estate under development	4,287,101		4,733,762
Other assets	158,145		139,562
Total assets	4,445,246		4,873,324
Debt	2,522,407		2,442,213
Other liabilities	181,761		117,160
Equity	1,741,078		2,313,951
Total liabilities and equity	4,445,246		4,873,324
Company's share of equity	997,137		$ 1,335,339
Equity Method Investment, Summarized Financial Information, Income Statement [Abstract]
Property revenues	77,369	83,725
Property operating expenses	(25,715)	(28,719)
Net operating income	51,654	55,006
Interest expense	(20,853)	(15,115)
General and administrative	(4,083)	(1,928)
Depreciation and amortization	(28,437)	(29,935)
Net income (loss)	(1,719)	8,028
Company's share of net income	21,297	16,276
Total co-investment | Affiliated Entity
Equity Method Investment, Summarized Financial Information, Income Statement [Abstract]
Company's share of net income	$ 2,100	$ 1,700