Segment Reporting - Reconciliation Of Segment Profit To Net Income Attributable To Common Stockholders (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting [Abstract]
Total profit from all segments	$ 135,867	$ 128,493	$ 269,516	$ 243,151
General and administrative	(8,592)	(9,403)	(18,748)	(17,474)
Depreciation and amortization	(68,793)	(62,568)	(136,167)	(118,120)
Other income	2,331	2,143	4,493	4,232
Other expenses	(1,773)	(1,908)	(3,497)	(4,912)
Income, including depreciation, from unconsolidated real estate funds	1,113	1,644	3,290	3,230
Interest expense	(38,000)	(37,703)	(74,954)	(73,363)
Income before gains	22,153	20,698	43,933	36,744
Gains on sales of investments in real estate	0	1,082	0	1,082
Net income	22,153	21,780	43,933	37,826
Less: Net income attributable to noncontrolling interests	(1,909)	(3,298)	(4,640)	(3,978)
Net income attributable to common stockholders	$ 20,244	$ 18,482	$ 39,293	$ 33,848