Segment Reporting - Reconciliation of Segment Profit to Net Income Attributable to Common Stockholders (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting [Abstract]
Total profit from all segments									$ 600,449	$ 554,018	$ 504,688
General and administrative									(38,641)	(36,234)	(34,957)
Depreciation and amortization									(309,864)	(276,761)	(248,914)
Other income									11,414	9,712	8,759
Other expenses									(7,472)	(7,037)	(9,477)
Income, including depreciation, from unconsolidated real estate funds									6,400	5,905	7,812
Interest expense									(133,402)	(145,176)	(146,148)
Demolition expenses									(272)	0	0
Income before gains									128,612	104,427	81,763
Gains on sales of investments in real estate									0	0	14,327
Net income	$ 23,532	$ 35,416	$ 37,033	$ 32,631	$ 31,986	$ 28,508	$ 22,153	$ 21,780	128,612	104,427	96,090
Less: Net income attributable to noncontrolling interests									(12,526)	(9,984)	(10,693)
Net income attributable to common stockholders	$ 25,635	$ 30,561	$ 31,684	$ 28,206	$ 29,536	$ 25,614	$ 20,244	$ 19,049	$ 116,086	$ 94,443	$ 85,397