CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (UNAUDITED) - USD ($) $ in Thousands	Total	Previously Reported [Member]	Restatement Adjustment [Member]	Common Stock [Member]	Common Stock [Member] Previously Reported [Member]	Additional Paid in Capital [Member]	Additional Paid in Capital [Member] Previously Reported [Member]	Earnings Less than Distributions [Member]	Earnings Less than Distributions [Member] Previously Reported [Member]	Earnings Less than Distributions [Member] Restatement Adjustment [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Accumulated Other Comprehensive (Loss) Income [Member] Previously Reported [Member]	Noncontrolling Interest Consolidated Joint Ventures [Member]	Noncontrolling Interest Consolidated Joint Ventures [Member] Previously Reported [Member]	Noncontrolling Interest Consolidated Real Estate Fund [Member]	Noncontrolling Interest Consolidated Real Estate Fund [Member] Previously Reported [Member]	Noncontrolling Interest Consolidated Real Estate Fund [Member] Restatement Adjustment [Member]	Noncontrolling Interest Operating Partnership [Member]	Noncontrolling Interest Operating Partnership [Member] Previously Reported [Member]
Beginning balance at Dec. 31, 2017	$ 5,029,170	$ 5,022,084		$ 2,403	$ 2,403	$ 4,297,948	$ 4,297,948	$ (133,164)	$ (133,693)		$ 10,083	$ 10,083	$ 404,997	$ 404,997	$ 21,106	$ 14,549		$ 425,797	$ 425,797
Beginning balance (Basis adjustment upon adoption of ASU 2017-05) at Dec. 31, 2017			$ 7,086							$ 529							$ 6,557
Common stock, shares outstanding at Dec. 31, 2017				240,427,000	240,427,000
Net (loss) income	(33,863)							(33,702)					2,807		582			(3,550)
Common shares issued upon redemption of common units						469
Common shares issued upon redemption of common units				27,000
Redemption of minority interest in operating partnerships																		(469)
Common shares issued under Omnibus share plan, net of shares withheld for taxes	(213)							(213)
Common shares issued under Omnibus share plan, net of shares withheld for taxes				75,000
Dividends and distributions	(53,247)							(48,103)										(5,144)
Contributions from noncontrolling interests	36,128														36,128
Distributions to noncontrolling interests	(4,118)												(4,118)
Change in value of interest rate swaps	20,346										18,422							1,924
Pro rata share of other comprehensive income (loss) of unconsolidated joint ventures	157										142							15
Amortization of equity awards	11,558					1,470												10,088
Other	(170)					(2,064)		(171)										2,065
Ending balance at Jun. 30, 2018	5,005,748			$ 2,403		4,297,823		(215,353)			28,647		403,686		57,816			430,726
Common stock, shares outstanding at Jun. 30, 2018				240,529,000
Beginning balance at Mar. 31, 2018	5,054,070			$ 2,403		4,293,209		(156,485)			23,312		404,137		51,456			436,038
Common stock, shares outstanding at Mar. 31, 2018				240,506,000
Net (loss) income	(36,578)							(34,816)					1,752		152			(3,666)
Common shares issued upon redemption of common units						346
Common shares issued upon redemption of common units				20,000
Redemption of minority interest in operating partnerships																		(346)
Common shares issued under Omnibus share plan, net of shares withheld for taxes				3,000
Dividends and distributions	(26,620)							(24,052)										(2,568)
Contributions from noncontrolling interests	6,208														6,208
Distributions to noncontrolling interests	(2,203)												(2,203)
Change in value of interest rate swaps	5,795										5,243							552
Pro rata share of other comprehensive income (loss) of unconsolidated joint ventures	103										92							11
Amortization of equity awards	4,974					632												4,342
Other	(1)					3,636												(3,637)
Ending balance at Jun. 30, 2018	5,005,748			$ 2,403		4,297,823		(215,353)			28,647		403,686		57,816			430,726
Common stock, shares outstanding at Jun. 30, 2018				240,529,000
Beginning balance at Dec. 31, 2018	$ 4,891,664			$ 2,329		4,201,756		(219,906)			16,621		394,995		66,887			428,982
Common stock, shares outstanding at Dec. 31, 2018	233,135,704			233,136,000
Net (loss) income	$ 12,174							6,164					5,202		147			661
Common shares issued upon redemption of common units				$ 14		23,976
Common shares issued upon redemption of common units				1,406,000
Redemption of minority interest in operating partnerships																		(23,990)
Common shares issued under Omnibus share plan, net of shares withheld for taxes	(307)			$ 3				(310)
Common shares issued under Omnibus share plan, net of shares withheld for taxes				56,000
Repurchases of common shares	(6,488)			$ (5)		(6,483)
Repurchases of common shares, shares				(474,000)
Dividends and distributions	(51,902)							(46,887)										(5,015)
Contributions from noncontrolling interests	14,966														14,966
Distributions to noncontrolling interests	(34,919)												(34,919)
Change in value of interest rate swaps	(24,371)										(22,026)							(2,345)
Pro rata share of other comprehensive income (loss) of unconsolidated joint ventures	(184)										(120)				(51)			(13)
Amortization of equity awards	12,756					1,340												11,416
Other						(6,396)												6,396
Ending balance at Jun. 30, 2019	$ 4,813,389			$ 2,341		4,214,193		(260,939)			(5,525)		365,278		81,949			416,092
Common stock, shares outstanding at Jun. 30, 2019	234,123,611			234,124,000
Beginning balance at Mar. 31, 2019	$ 4,854,636			$ 2,345		4,218,060		(239,949)			8,421		367,012		81,434			417,313
Common stock, shares outstanding at Mar. 31, 2019				234,478,000
Net (loss) income	5,174							2,455					2,408		53			258
Common shares issued upon redemption of common units				$ 1		2,007
Common shares issued upon redemption of common units				118,000
Redemption of minority interest in operating partnerships																		(2,008)
Common shares issued under Omnibus share plan, net of shares withheld for taxes	(6)							(6)
Common shares issued under Omnibus share plan, net of shares withheld for taxes				2,000
Repurchases of common shares	$ (6,488)			$ (5)		(6,483)
Repurchases of common shares, shares	(474,500)			(474,000)
Dividends and distributions	$ (25,953)							(23,439)										(2,514)
Contributions from noncontrolling interests	470														470
Distributions to noncontrolling interests	(4,142)												(4,142)
Change in value of interest rate swaps	(15,345)										(13,884)							(1,461)
Pro rata share of other comprehensive income (loss) of unconsolidated joint ventures	(76)										(62)				(8)			(6)
Amortization of equity awards	5,119					643												4,476
Other						(34)												34
Ending balance at Jun. 30, 2019	$ 4,813,389			$ 2,341		$ 4,214,193		$ (260,939)			$ (5,525)		$ 365,278		$ 81,949			$ 416,092
Common stock, shares outstanding at Jun. 30, 2019	234,123,611			234,124,000