Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Limited Partner [Member]	General Partner [Member]	AOCI Attributable to Noncontrolling Interest [Member]	Noncontrolling Interests-Consolidated Real Estate Entities [Member]	Redeemable Common Stock [Member]	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Distributions in Excess Of Net Income [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Noncontrolling Interests Operating Partnership [Member]	Noncontrolling Interests-Consolidated Real Estate Entities [Member]	Redeemable Common Stock [Member]
Beginning Balance at Dec. 31, 2016	$ 6,642,101						$ 9	$ 1,133	$ 7,109,012	$ (707,479)	$ 1,144	$ 235,976	$ 2,306	$ 10,073
Beginning Balance, Shares at Dec. 31, 2016							868	113,415
Net income	340,536	$ 12,157								328,379		12,157
Other comprehensive income - derivative instruments	1,049			$ 1,049							1,013	36
Issuance and registration of common shares	616							$ 1	615					1,588
Issuance and registration of common shares, Shares								137
Issuance and registration of preferred shares	2,007								2,007
Shares repurchased and retired	(4,782)		$ (4,782)						(4,782)
Shares repurchased and retired, Shares								(51)
Exercise of stock options	218		218						218
Exercise of stock options, Shares								10
Shares issued in exchange for common units									1,602			(1,602)
Shares issued in exchange for common units, Shares								29
Shares issued in exchange for redeemable stock	1,482		1,482			$ (1,482)			1,482					(1,482)
Redeemable stock fair market value adjustment	(229)		(229)			229				(229)				229
Adjustment for noncontrolling interests in Operating Partnership		(6)	6						42			(42)
Amortization of unearned compensation	10,802								10,916	(114)
Dividends on preferred stock	(3,688)									(3,688)
Dividends on common stock	(401,369)									(401,369)
Dividends on noncontrolling interests units	(14,849)											(14,849)
Ending Balance at Dec. 31, 2017	6,573,894						$ 9	$ 1,134	7,121,112	(784,500)	2,157	231,676	2,306	10,408
Ending Balance, Shares at Dec. 31, 2017							868	113,540
Partners' Capital at Dec. 31, 2016	6,642,082	235,976	6,337,721	1,246	$ 2,306	10,073				64,833
Net Income (Loss) Allocated to General Partners			324,691
Dividends, Preferred Stock, Cash	3,688									3,688
Issuance of units	2,623		616			1,588				2,007
General partner units issued in exchange for limited partner units		(1,602)	1,602
Amortization of unearned compensation	10,802		10,802
Dividends, Preferred Stock, Cash	(3,688)
Distributions to common unitholders	(416,218)	(14,849)	(401,369)
Partners' Capital at Dec. 31, 2017	6,573,875	231,676	6,270,758	2,295	2,306	10,408				66,840
Net income	231,022	8,123								222,899		8,123
Other comprehensive income - derivative instruments	(2,689)			(2,689)							(2,602)	(87)
Issuance and registration of common shares	(263)							$ 1	(264)					1,482
Issuance and registration of common shares, Shares								142
Shares repurchased and retired	(2,921)		(2,921)						(2,921)
Shares repurchased and retired, Shares								(34)
Exercise of stock options	916		916						916
Exercise of stock options, Shares								18
Shares issued in exchange for common units								$ 1	4,443			(4,444)
Shares issued in exchange for common units, Shares								80
Shares issued in exchange for redeemable stock	1,915		1,915			(1,915)			1,915					(1,915)
Redeemable stock fair market value adjustment	561		561			(561)				561				(561)
Adjustment for noncontrolling interests in Operating Partnership		(153)	153						66			(66)
Cumulative adjustment due to adoption of ASU 2017-12			(233)	233						(233)	233
Amortization of unearned compensation	12,903								12,903
Dividends on preferred stock	(3,688)									(3,688)
Dividends on common stock	(424,302)									(424,302)
Dividends on noncontrolling interests units	(15,159)											(15,159)
Ending Balance at Dec. 31, 2018	6,372,189						$ 9	$ 1,136	7,138,170	(989,263)	(212)	220,043	2,306	9,414
Ending Balance, Shares at Dec. 31, 2018							868	113,746
Net Income (Loss) Allocated to General Partners			219,211
Dividends, Preferred Stock, Cash	3,688									3,688
Issuance of units	(264)		(264)			1,482
General partner units issued in exchange for limited partner units		(4,444)	4,444
Amortization of unearned compensation	12,904		12,904
Dividends, Preferred Stock, Cash	(3,688)									(3,688)
Distributions to common unitholders	(439,461)	(15,159)	(424,302)
Partners' Capital at Dec. 31, 2018	6,372,170	220,043	6,083,142	(161)	2,306	9,414				66,840
Net income	366,618	12,671			136					353,811		12,671	136
Other comprehensive income - derivative instruments	(13,423)			(13,423)							(12,966)	(457)
Issuance and registration of common shares	20,500							$ 4	20,496					1,651
Issuance and registration of common shares, Shares								338
Shares repurchased and retired	(3,724)		(3,724)						(3,724)
Shares repurchased and retired, Shares								(37)
Exercise of stock options	$ 2,881		2,881						2,881
Exercise of stock options, Shares	69,852							48
Shares issued in exchange for common units									2,366			(2,366)
Shares issued in exchange for common units, Shares								44
Shares issued in exchange for redeemable stock	$ 575		575			(575)			575					(575)
Redeemable stock fair market value adjustment	(3,641)		(3,641)			3,641				(3,641)				3,641
Adjustment for noncontrolling interests in Operating Partnership	6,126	359	(359)		6,126				(816)			816
Amortization of unearned compensation	14,684								14,684
Dividends on preferred stock	(3,688)									(3,688)
Dividends on common stock	(442,698)									(442,698)
Dividends on noncontrolling interests units	(16,060)											(16,060)
Acquisition of noncontrolling interest	(10,880)		(8,559)		(2,321)				(8,559)				(2,321)
Contributions From Non Controlling Interest	6,126												6,126
Ending Balance at Dec. 31, 2019	6,289,459						$ 9	$ 1,140	$ 7,166,073	(1,085,479)	$ (13,178)	$ 214,647	$ 6,247	$ 14,131
Ending Balance, Shares at Dec. 31, 2019							868	114,139
Net Income (Loss) Allocated to General Partners			350,123
Dividends, Preferred Stock, Cash	3,688									3,688
Issuance of units	20,500		20,500			1,651
General partner units issued in exchange for limited partner units		(2,366)	2,366
Amortization of unearned compensation	14,684		14,684
Dividends, Preferred Stock, Cash	(3,688)
Distributions to common unitholders	(458,758)	(16,060)	(442,698)
Partners' Capital at Dec. 31, 2019	$ 6,289,440	$ 214,647	$ 6,015,290	$ (13,584)	$ 6,247	$ 14,131				$ 66,840