CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (UNAUDITED) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid in Capital [Member]	Earnings Less than Distributions [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Noncontrolling Interest [Member] Consolidated Joint Ventures [Member]	Noncontrolling Interest [Member] Consolidated Real Estate Fund [Member]	Noncontrolling Interest [Member] Operating Partnership [Member]
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		233,136,000
Net (loss) 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		(6,726,000)
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)
Reallocation of noncontrolling interest			(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		227,866,000
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 (loss) 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)
Reallocation of noncontrolling interest			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		227,866,000
Beginning balance at Dec. 31, 2019	$ 4,630,962	$ 2,274	4,133,184	(349,557)	(171)	360,778	72,396	412,058
Common stock, shares outstanding at Dec. 31, 2019	227,432,030	227,432,000
Net (loss) income	$ (6,581)			(9,880)		5,485	(1,291)	(895)
Common shares issued upon redemption of common units		$ 51	85,659
Common shares issued upon redemption of common units		5,150,000
Redemption of minority interest in operating partnerships								(85,710)
Common shares issued under Omnibus share plan, net of shares withheld for taxes	(318)	$ 1		(319)
Common shares issued under Omnibus share plan, net of shares withheld for taxes		53,000
Repurchases of common shares	(108,520)	$ (121)	(108,399)
Repurchases of common shares, shares		(12,090,000)
Dividends and distributions	(72,807)			(66,482)				(6,325)
Contributions from noncontrolling interests	11,555					3,500	8,055
Distributions to noncontrolling interests	(9,530)					(9,530)
Pro rata share of other comprehensive income (loss) of unconsolidated joint ventures	(15,453)				(14,037)		8	(1,424)
Amortization of equity awards	14,252		984					13,268
Sale of a 10.0% interest in 1633 Broadway	109,573		33,230			76,343
Reallocation of noncontrolling interest			(16,171)					16,171
Ending balance at Sep. 30, 2020	$ 4,553,133	$ 2,205	4,128,487	(426,238)	(14,208)	436,576	79,168	347,143
Common stock, shares outstanding at Sep. 30, 2020	220,545,325	220,545,000
Beginning balance at Jun. 30, 2020	$ 4,587,676	$ 2,219	4,133,542	(397,220)	(15,031)	436,183	79,243	348,740
Common stock, shares outstanding at Jun. 30, 2020		221,764,000
Net (loss) income	(4,123)			(6,958)		3,566	(79)	(652)
Common shares issued upon redemption of common units			399
Common shares issued upon redemption of common units		24,000
Redemption of minority interest in operating partnerships								(399)
Common shares issued under Omnibus share plan, net of shares withheld for taxes	(2)	$ (2)
Common shares issued under Omnibus share plan, net of shares withheld for taxes		(10,000)
Repurchases of common shares	(8,520)	$ (12)	(8,508)
Repurchases of common shares, shares		(1,233,190)
Dividends and distributions	(24,173)			(22,060)				(2,113)
Distributions to noncontrolling interests	(3,173)					(3,173)
Pro rata share of other comprehensive income (loss) of unconsolidated joint ventures	904				823		4	77
Amortization of equity awards	4,544		292					4,252
Reallocation of noncontrolling interest			2,762					(2,762)
Ending balance at Sep. 30, 2020	$ 4,553,133	$ 2,205	$ 4,128,487	$ (426,238)	$ (14,208)	$ 436,576	$ 79,168	$ 347,143
Common stock, shares outstanding at Sep. 30, 2020	220,545,325	220,545,000