Co-investments - Combined Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Equity Method Investment, Summarized Financial Information, Assets [Abstract] (Deprecated 2020-01-31)
Rental properties and real estate under development	$ 467,915		$ 467,915			$ 546,075
Total assets	13,177,411		13,177,411			12,705,405
Debt	6,791,289		6,791,289			6,264,491
Other liabilities	40,473		40,473			36,565
Cumulative effect upon adoption of ASU No. 2016-13	6,352,881	$ 6,345,116	6,352,881	$ 6,345,116	$ 6,417,949	6,403,504	$ 6,317,195	$ 6,393,844
Total liabilities and equity	13,177,411		13,177,411			12,705,405
Equity Method Investment, Summarized Financial Information, Income Statement [Abstract] (Deprecated 2020-01-31)
Property revenues	370,497	361,635	762,864	717,858
Interest expense	(54,447)	(54,112)	(109,594)	(107,755)
General and administrative	(14,952)	(13,927)	(28,934)	(27,386)
Net income	90,076	98,061	418,841	223,566
Total co-investment | Affiliated Entity
Equity Method Investment, Summarized Financial Information, Income Statement [Abstract] (Deprecated 2020-01-31)
Company's share of net income	2,100	1,800	4,200	3,500
Equity Method Investment, Nonconsolidated Investee or Group of Investees | Total co-investment
Equity Method Investment, Summarized Financial Information, Assets [Abstract] (Deprecated 2020-01-31)
Rental properties and real estate under development	4,398,987		4,398,987			4,733,762
Other assets	215,425		215,425			139,562
Total assets	4,614,412		4,614,412			4,873,324
Debt	2,716,143		2,716,143			2,442,213
Other liabilities	164,951		164,951			117,160
Cumulative effect upon adoption of ASU No. 2016-13	1,733,318		1,733,318			2,313,951
Total liabilities and equity	4,614,412		4,614,412			4,873,324
Company's share of equity	1,008,758		1,008,758			$ 1,335,339
Equity Method Investment, Summarized Financial Information, Income Statement [Abstract] (Deprecated 2020-01-31)
Property revenues	72,175	81,832	149,544	165,557
Property operating expenses	(25,859)	(27,835)	(51,574)	(56,554)
Net operating income	46,316	53,997	97,970	109,003
Interest expense	(19,478)	(16,080)	(40,331)	(31,195)
General and administrative	(3,392)	(2,243)	(7,475)	(4,171)
Depreciation and amortization	(28,778)	(28,937)	(57,215)	(58,872)
Net income	(5,332)	6,737	(7,051)	14,765
Company's share of net income	$ 17,257	$ 16,959	$ 38,554	$ 33,235