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
Beginning balance (in shares) at Dec. 31, 2017			140,993,985
Beginning 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
Net income (loss)	(25,515)	(25,757)			(25,757)		242
Interest rate cap/swap agreements	9	9				9
Amortization of share and unit-based plans (in shares)			118,407
Amortization of share and unit-based plans	23,603	23,603	$ 1	23,602
Employee stock purchases (in shares)			17,240
Employee stock purchases	806	806		806
Distributions declared	(208,847)	(208,847)			208,847
Distributions to noncontrolling interests	(17,898)						(17,898)
Conversion of noncontrolling interests to common shares (in shares)			54,703
Conversion of noncontrolling interests to common shares	0	75	$ 1	74			(75)
Redemption of noncontrolling interests	(123)	(84)		84			(39)
Adjustment of noncontrolling interests in Operating Partnership	0	23,986		23,986			(23,986)
Ending balance (in shares) at Jun. 30, 2018			141,184,335
Ending balance at Jun. 30, 2018	3,315,175	3,070,510	$ 1,412	4,558,873	(1,489,742)	(33)	244,665
Beginning balance (in shares) at Mar. 31, 2018			141,104,587
Beginning balance at Mar. 31, 2018	3,408,585	3,157,760	$ 1,411	4,549,748	(1,393,418)	19	250,825
Increase (Decrease) in Stockholders' Equity
Net income (loss)	8,866	7,816			7,816		1,050
Interest rate cap/swap agreements	(52)	(52)				(52)
Amortization of share and unit-based plans (in shares)			8,805
Amortization of share and unit-based plans	9,991	9,991		9,991
Employee stock purchases (in shares)			17,240
Employee stock purchases	806	806		806
Distributions declared	(104,140)	(104,140)			104,140
Distributions to noncontrolling interests	(8,823)						(8,823)
Conversion of noncontrolling interests to common shares (in shares)			53,703
Conversion of noncontrolling interests to common shares	0	75	$ 1	74			(75)
Redemption of noncontrolling interests	(58)	(38)		38			(20)
Adjustment of noncontrolling interests in Operating Partnership	0	(1,708)		(1,708)			1,708
Ending balance (in shares) at Jun. 30, 2018			141,184,335
Ending balance at Jun. 30, 2018	$ 3,315,175	3,070,510	$ 1,412	4,558,873	(1,489,742)	(33)	244,665
Beginning balance (in shares) at Dec. 31, 2018	141,221,712		141,221,712
Beginning balance at Dec. 31, 2018	$ 3,188,432	2,950,232	$ 1,412	4,567,643	(1,614,357)	(4,466)	238,200
Increase (Decrease) in Stockholders' Equity
Net income (loss)	22,790	23,558			23,558		(768)
Interest rate cap/swap agreements	(6,326)	(6,326)				(6,326)
Amortization of share and unit-based plans (in shares)			95,056
Amortization of share and unit-based plans	10,038	10,038	$ 1	10,037
Employee stock purchases (in shares)			26,800
Employee stock purchases	819	819		819
Distributions declared	(212,095)	(212,095)			212,095
Distributions to noncontrolling interests	(32,458)						(32,458)
Contributions from noncontrolling interests	410						410
Conversion of noncontrolling interests to common shares (in shares)			21,000
Conversion of noncontrolling interests to common shares	0	1,005		1,005			(1,005)
Redemption of noncontrolling interests	(37)	(20)		20			(17)
Adjustment of noncontrolling interests in Operating Partnership	$ 0	(864)		(864)			864
Ending balance (in shares) at Jun. 30, 2019	141,364,568		141,364,568
Ending balance at Jun. 30, 2019	$ 2,969,370	2,764,144	$ 1,413	4,578,620	(1,805,097)	(10,792)	205,226
Beginning balance (in shares) at Mar. 31, 2019			141,332,786
Beginning balance at Mar. 31, 2019	3,085,269	2,854,713	$ 1,413	4,574,600	(1,714,789)	(6,511)	230,556
Increase (Decrease) in Stockholders' Equity
Net income (loss)	13,947	15,734			15,734		(1,787)
Interest rate cap/swap agreements	(4,281)	(4,281)				(4,281)
Amortization of share and unit-based plans (in shares)			4,982
Amortization of share and unit-based plans	3,373	3,373		3,373
Employee stock purchases (in shares)			26,800
Employee stock purchases	819	819		819
Distributions declared	(106,042)	(106,042)			106,042
Distributions to noncontrolling interests	(24,115)						(24,115)
Contributions from noncontrolling interests	410						410
Redemption of noncontrolling interests	(10)	(5)		5			(5)
Adjustment of noncontrolling interests in Operating Partnership	$ 0	(167)		(167)			167
Ending balance (in shares) at Jun. 30, 2019	141,364,568		141,364,568
Ending balance at Jun. 30, 2019	$ 2,969,370	$ 2,764,144	$ 1,413	$ 4,578,620	$ (1,805,097)	$ (10,792)	$ 205,226