CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Total	Total Stockholders' Equity	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Loss	Noncontrolling Interests
Balance (in shares) at Dec. 31, 2014			158,201,996
Balance at Dec. 31, 2014	$ 6,039,849	$ 5,640,120	$ 1,582	$ 5,041,797	$ 596,741		$ 399,729
Increase (Decrease) in Stockholders' Equity
Net income	522,912	487,562			487,562		35,350
Interest rate cap	0
Amortization of share and unit-based plans (in shares)			241,186
Amortization of share and unit-based plans	34,375	34,375	$ 2	34,373
Employee stock purchases (in shares)			23,036
Employee stock purchases	1,512	1,512		1,512
Stock repurchase (in shares)			(4,140,788)
Stock repurchase	(400,144)	(400,144)	$ (41)	(153,602)	(246,501)
Distributions	(1,050,562)	(1,050,562)			(1,050,562)
Distributions to noncontrolling interests	(74,677)						(74,677)
Contributions from noncontrolling interests	23						23
Other	(1,593)	(1,593)		(1,593)
Conversion of noncontrolling interests to common shares (in shares)			79,556
Conversion of noncontrolling interests to common shares	0	1,559	$ 1	1,558			(1,559)
Redemption of noncontrolling interests	(456)	(343)		(343)			(113)
Adjustment of noncontrolling interests in Operating Partnership	0	2,928		2,928			(2,928)
Balance (in shares) at Dec. 31, 2015			154,404,986
Balance at Dec. 31, 2015	5,071,239	4,715,414	$ 1,544	4,926,630	(212,760)		355,825
Increase (Decrease) in Stockholders' Equity
Net income	554,839	516,995			516,995		37,844
Interest rate cap	0
Amortization of share and unit-based plans (in shares)			139,671
Amortization of share and unit-based plans	40,529	40,529	$ 2	40,527
Employee stock purchases (in shares)			28,147
Employee stock purchases	1,697	1,697		1,697
Stock repurchase (in shares)			(11,123,011)
Stock repurchase	(800,018)	(800,018)	$ (111)	(412,391)	(387,516)
Distributions	(405,501)	(405,501)			(405,501)
Distributions to noncontrolling interests	(35,677)						(35,677)
Contributions from noncontrolling interests	90						90
Conversion of noncontrolling interests to common shares (in shares)			535,243
Conversion of noncontrolling interests to common shares	0	12,448	$ 5	12,443			(12,448)
Redemption of noncontrolling interests	(30)	(23)		(23)			(7)
Adjustment of noncontrolling interests in Operating Partnership	$ 0	24,346		24,346			(24,346)
Balance (in shares) at Dec. 31, 2016	143,958,036		143,985,036
Balance at Dec. 31, 2016	$ 4,427,168	4,105,887	$ 1,440	4,593,229	(488,782)	$ 0	321,281
Increase (Decrease) in Stockholders' Equity
Net income	161,673	146,130			146,130		15,543
Interest rate cap	(42)	(42)				(42)
Amortization of share and unit-based plans (in shares)			97,694
Amortization of share and unit-based plans	37,005	37,005	$ 1	37,004
Employee stock purchases (in shares)			38,832
Employee stock purchases	1,868	1,868		1,868
Stock repurchase (in shares)			(3,627,390)
Stock repurchase	(221,428)	(221,428)	$ (36)	(135,176)	(86,216)
Distributions	(407,895)	(407,895)			(407,895)
Distributions to noncontrolling interests	(35,944)						(35,944)
Contributions from noncontrolling interests	30						30
Conversion of noncontrolling interests to common shares (in shares)			499,813
Conversion of noncontrolling interests to common shares	0	16,797	$ 5	16,792			(16,797)
Redemption of noncontrolling interests	(920)	(615)		(615)			(305)
Adjustment of noncontrolling interests in Operating Partnership	$ 0	(2,613)		(2,613)			2,613
Balance (in shares) at Dec. 31, 2017	140,993,985		140,993,985
Balance at Dec. 31, 2017	$ 3,967,999	3,681,578	$ 1,410	$ 4,510,489	(830,279)	$ (42)	$ 286,421
Increase (Decrease) in Stockholders' Equity
Cumulative effect of adoption of ASU 2016-09	$ 6,484	$ 6,484			$ 6,484