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 income	10,398							3,829					5,520		668			381
Common shares issued upon redemption of common units				$ 2		3,459
Common shares issued upon redemption of common units				203,000
Redemption of minority interest in operating partnerships																		(3,461)
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				68,000
Repurchases of common shares	(3,569)			$ (3)		(3,566)
Repurchases of common shares, shares				(237,000)
Dividends and distributions	(79,843)							(72,149)										(7,694)
Contributions from noncontrolling interests	44,381														44,381
Distributions to noncontrolling interests	(10,583)												(10,583)
Change in value of interest rate swaps	23,738										21,492							2,246
Pro rata share of other comprehensive income (loss) of unconsolidated joint ventures	(105)										(44)				(56)			(5)
Amortization of equity awards	16,209					2,206												14,003
Other	(171)					1,282		(171)			(1)							(1,281)
Ending balance at Sep. 30, 2018	5,029,412			$ 2,402		4,301,329		(201,868)			31,530		399,934		66,099			429,986
Common stock, shares outstanding at Sep. 30, 2018				240,461,000
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
Repurchases of common shares	$ (105,383)
Repurchases of common shares, shares	(7,555,601)
Ending 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
Beginning 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
Net income	44,261							37,531					2,713		86			3,931
Common shares issued upon redemption of common units				$ 2		2,990
Common shares issued upon redemption of common units				176,000
Redemption of minority interest in operating partnerships																		(2,992)
Common shares issued under Omnibus share plan, net of shares withheld for taxes				(7,000)
Repurchases of common shares	(3,569)			$ (3)		(3,566)
Repurchases of common shares, shares				(237,000)
Dividends and distributions	(26,596)							(24,046)										(2,550)
Contributions from noncontrolling interests	8,253														8,253
Distributions to noncontrolling interests	(6,465)												(6,465)
Change in value of interest rate swaps	3,392										3,070							322
Pro rata share of other comprehensive income (loss) of unconsolidated joint ventures	(262)										(186)				(56)			(20)
Amortization of equity awards	4,651					736												3,915
Other	(1)					3,346					(1)							(3,346)
Ending balance at Sep. 30, 2018	5,029,412			$ 2,402		4,301,329		(201,868)			31,530		399,934		66,099			429,986
Common stock, shares outstanding at Sep. 30, 2018				240,461,000
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 income	$ 23,174							13,246					8,253		256			1,419
Common shares issued upon redemption of common units				$ 14		23,992
Common shares issued upon redemption of common units				1,407,000
Redemption of minority interest in operating partnerships																		(24,006)
Common shares issued under Omnibus share plan, net of shares withheld for taxes	(314)			$ 3				(317)
Common shares issued under Omnibus share plan, net of shares withheld for taxes				49,000
Repurchases of common shares	$ (89,005)			$ (67)		(88,938)
Repurchases of common shares, shares	(6,726,203)			(6,726,000)
Dividends and distributions	$ (77,209)							(69,682)										(7,527)
Contributions from noncontrolling interests	14,989														14,989
Distributions to noncontrolling interests	(40,037)												(40,037)
Change in value of interest rate swaps	(28,502)										(25,757)							(2,745)
Pro rata share of other comprehensive income (loss) of unconsolidated joint ventures	(143)										(83)				(51)			(9)
Amortization of equity awards	17,966					1,984												15,982
Acquisition of noncontrolling interest	(9,840)														(9,840)
Other						(4,405)												4,405
Ending balance at Sep. 30, 2019	$ 4,702,743			$ 2,279		4,134,389		(276,659)			(9,219)		363,211		72,241			416,501
Common stock, shares outstanding at Sep. 30, 2019	227,865,810			227,866,000
Beginning 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				234,124,000
Net income	11,000							7,082					3,051		109			758
Common shares issued upon redemption of common units						16
Common shares issued upon redemption of common units				1,000
Redemption of minority interest in operating partnerships																		(16)
Common shares issued under Omnibus share plan, net of shares withheld for taxes	(7)							(7)
Common shares issued under Omnibus share plan, net of shares withheld for taxes				(7,000)
Repurchases of common shares	(82,517)			$ (62)		(82,455)
Repurchases of common shares, shares				(6,252,000)
Dividends and distributions	(25,307)							(22,795)										(2,512)
Contributions from noncontrolling interests	23														23
Distributions to noncontrolling interests	(5,118)												(5,118)
Change in value of interest rate swaps	(4,131)										(3,731)							(400)
Pro rata share of other comprehensive income (loss) of unconsolidated joint ventures	41										37							4
Amortization of equity awards	5,210					644												4,566
Acquisition of noncontrolling interest	(9,840)														(9,840)
Other						1,991												(1,991)
Ending balance at Sep. 30, 2019	$ 4,702,743			$ 2,279		$ 4,134,389		$ (276,659)			$ (9,219)		$ 363,211		$ 72,241			$ 416,501
Common stock, shares outstanding at Sep. 30, 2019	227,865,810			227,866,000