Consolidated Statements of Equity - USD ($)	General Partners' Capital Account [Member]	Common Stock	Additional Paid-in Capital	Limited Partner [Member]	Limited Partner [Member] Limited Partners' Capital Account [Member]	Limited Partner [Member] General Partners' Capital Account [Member]	Limited Partner [Member] Total Partnership Capital [Member]	Limited Partner [Member] AOCI Attributable to Noncontrolling Interest [Member]	Limited Partner [Member] Limited Partner [Member]	Limited Partner [Member] Redeemable Stock	Limited Partner [Member] Accumulated Distributions in Excess of Net Income	Parent Company [Member]	Parent Company [Member] Preferred Stock Including Additional Paid in Capital [Member]	Parent Company [Member] Preferred Stock [Member]	Parent Company [Member] Common Stock	Parent Company [Member] Common Stock Including Additional Paid in Capital [Member]	Parent Company [Member] Additional Paid-in Capital	Parent Company [Member] Accumulated Distributions in Excess of Net Income	Parent Company [Member] Noncontrolling Interest	Parent Company [Member] Redeemable Stock	Parent Company [Member] Accumulated Other Comprehensive Income (Loss) [Member]	Stockholders' Equity, Total [Member] Limited Partner [Member]	Stockholders' Equity, Total [Member] Parent Company [Member]
Noncontrolling Interest in Joint Ventures				$ 0
Common Stock, Dividends, Per Share, Declared												$ 3.3300
Shares, Outstanding at Dec. 31, 2015															75,318,000
Common stock shares issued (shares)															38,097,000
Common stock repurchased and retired (shares)															0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period															(23,000)
Stock Issued During Period, Shares, Conversion of Units															23,000
Shares, Outstanding at Dec. 31, 2016															113,415,000
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 31, 2015															$ 753,000		$ 3,627,074,000	$ (634,141,000)	$ 165,726,000		$ (1,589,000)		$ 3,157,823,000
Net Income Attributable to Parent																		212,222,000
Net Income Attributable to Noncontrolling Interest																			12,180,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest				224,402,000			$ 224,402,000					$ 224,402,000											224,402,000
Other comprehensive income - derivative instruments (cash flow hedges)							2,864,000	$ 2,864,000											131,000		2,733,000		2,864,000
Issuance and registration of common shares															380,000		3,406,150,000		72,759,000	$ 1,240,000			3,479,289,000
Proceeds from Issuance of Preferred Stock, Preference Stock, and Warrants																							64,833,000
Shares repurchased and retired															0		64,824,000						(2,019,000)
Exercise of stock options															0		(2,019,000)
Shares issued in exchange for units															0		902,000		(902,000)				0
Stock Issued in Exchange for Redeemable Stock																	122,000
Redeemable stock fair market value						$ 705,000	705,000			$ 705,000								705,000		705,000			(705,000)
Adjustment for Noncontrolling Interest Ownership in operating partnership						(323,000)	0		$ 323,000					$ 0			(192,000)		192,000				0
Amortization of unearned compensation						12,151,000	12,151,000							0			12,151,000						12,151,000
Dividends, Preferred Stock																		284,548,000
Payments of Ordinary Dividends					$ (226,000)
Payments of Ordinary Dividends, Noncontrolling Interest												13,850,000							(226,000)				(226,000)
Dividends, Preferred Stock, Cash				924,000							$ 307,000	924,000						307,000					307,000
Dividends on common stock														0				0					(284,548,000)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 31, 2016															$ 1,133,000		7,109,012,000	(707,479,000)	235,976,000		1,144,000		6,642,101,000
Redeemable stock at Dec. 31, 2015										8,250,000										8,250,000
Redeemable stock at Dec. 31, 2016										10,073,000										10,073,000
Partners' Capital at Dec. 31, 2015						2,993,696,000	3,157,804,000	(1,618,000)	165,726,000
Net Income (Loss) Allocated to Limited Partners									12,180,000
Net Income (Loss) Allocated to General Partners						211,915,000
Issuance of units				$ 64,833,000	72,759,000	3,406,530,000	3,544,122,000			1,240,000	64,833,000
Units repurchased and retired						(2,019,000)	(2,019,000)
General partnership units issued in exchange for limited partnership units						902,000	0		(902,000)
Partnership units issued in exchange for redeemable units						122,000	122,000			(122,000)										122,000			122,000
Distributions						(284,548,000)	(298,432,000)		(13,884,000)
Partners' Capital at Dec. 31, 2016					235,976,000	6,337,721,000	6,642,082,000	1,246,000
Dividends on noncontrolling interest units														$ 0					13,884,000				(13,884,000)
Distribution Made to Limited Partner, Distributions Declared, Per Unit				$ 3.3300
Preferred Stock, Shares Outstanding														868,000
Preferred Stock, Value, Outstanding														$ 9,000
Noncontrolling Interest in Joint Ventures				$ 2,306,000								$ 2,306,000											2,306,000
Common Stock, Dividends, Per Share, Declared												$ 3.5325
Common stock shares issued (shares)															137,000
Common stock repurchased and retired (shares)															51,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period															10,000
Stock Issued During Period, Shares, Conversion of Units															29,000
Shares, Outstanding at Dec. 31, 2017															113,540,000
Net Income Attributable to Parent																		328,379,000
Net Income Attributable to Noncontrolling Interest																			12,157,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest				340,536,000			340,536,000					$ 340,536,000		0									340,536,000
Other comprehensive income - derivative instruments (cash flow hedges)							1,049,000	1,049,000						0					36,000		1,013,000		1,049,000
Issuance and registration of common shares													$ 2,007,000	0	$ 1,000	$ 615,000			0	1,588,000			616,000
Proceeds from Issuance of Preferred Stock, Preference Stock, and Warrants																							2,007,000
Shares repurchased and retired		$ 0												0			(4,782,000)						(4,782,000)
Exercise of stock options		0	$ 218,000											0									218,000
Shares issued in exchange for units		$ 0												0			1,602,000		(1,602,000)				0
Stock Issued in Exchange for Redeemable Stock																	1,482,000
Redeemable stock fair market value						229,000	229,000			229,000				0				229,000		229,000			(229,000)
Adjustment for Noncontrolling Interest Ownership in operating partnership						6,000	0		(6,000)					0			42,000		(42,000)				0
Amortization of unearned compensation						10,802,000	10,802,000							0			10,916,000	(114,000)					10,802,000
Payments of Ordinary Dividends, Noncontrolling Interest												14,654,000
Dividends, Preferred Stock, Cash				3,688,000			(3,688,000)					3,688,000						3,688,000					3,688,000
Dividends on common stock														0				(401,369,000)					(401,369,000)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 31, 2017												6,571,588,000			$ 1,134,000		7,121,112,000	(784,500,000)	231,676,000		2,157,000		6,573,894,000
Redeemable stock at Dec. 31, 2017				10,408,000						10,408,000		$ 10,408,000								10,408,000
Net Income (Loss) Allocated to Limited Partners									12,157,000
Net Income (Loss) Allocated to General Partners						324,691,000
Issuance of units				$ 66,840,000	0	616,000	2,623,000			1,588,000
Units repurchased and retired						(4,782,000)	(4,782,000)
Exercise of unit options	$ 218,000						218,000
General partnership units issued in exchange for limited partnership units						1,602,000	0		(1,602,000)
Partnership units issued in exchange for redeemable units						1,482,000	1,482,000			(1,482,000)										1,482,000			1,482,000
Distributions						(401,369,000)	(416,218,000)		(14,849,000)
Partners' Capital at Dec. 31, 2017					231,676,000	6,270,758,000	6,573,875,000	2,295,000
Dividends on noncontrolling interest units														$ 0					(14,849,000)				(14,849,000)
Distribution Made to Limited Partner, Distributions Declared, Per Unit				$ 3.5325
Preferred Stock, Shares Outstanding												867,846		868,000
Preferred Stock, Value, Outstanding												$ 9,000		$ 9,000
Noncontrolling Interest in Joint Ventures				$ 2,306,000								$ 2,306,000
Common Stock, Dividends, Per Share, Declared												$ 3.7275
Common stock shares issued (shares)															142,000
Common stock repurchased and retired (shares)															34,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period															18,000
Stock Issued During Period, Shares, Conversion of Units															80,000
Shares, Outstanding at Dec. 31, 2018															113,746,000
Net Income Attributable to Parent																		222,899,000
Net Income Attributable to Noncontrolling Interest																			8,123,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest				231,022,000			231,022,000					$ 231,022,000		0									231,022,000
Other comprehensive income - derivative instruments (cash flow hedges)							(2,689,000)	(2,689,000)						0					(87,000)		(2,602,000)		(2,689,000)
Issuance and registration of common shares														0	$ 1,000	$ (264,000)			0	1,482,000			(263,000)
Shares repurchased and retired														0	0		(2,921,000)						(2,921,000)
Exercise of stock options															0		916,000						916,000
Shares issued in exchange for units														0	1,000		4,443,000		(4,444,000)				0
Stock Issued in Exchange for Redeemable Stock																	1,915,000			(1,915,000)			1,915,000
Redeemable stock fair market value						(561,000)	(561,000)			(561,000)				0				(561,000)		(561,000)			561,000
Adjustment for Noncontrolling Interest Ownership in operating partnership						153,000	0		(153,000)					0			66,000		(66,000)				0
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification						(233,000)											0	(233,000)	0		233,000		0
Amortization of unearned compensation						12,904,000	12,904,000							0			12,903,000	0					12,903,000
Payments of Ordinary Dividends, Noncontrolling Interest												15,079,000
Dividends, Preferred Stock, Cash				3,688,000								3,688,000						3,688,000				$ (3,688,000)	(3,688,000)
Dividends on common stock														0				(424,302,000)					(424,302,000)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 31, 2018												6,369,883,000			$ 1,136,000		$ 7,138,170,000	$ (989,263,000)	220,043,000		$ (212,000)		6,372,189,000
Redeemable stock at Dec. 31, 2018				$ 9,414,000						9,414,000		$ 9,414,000								$ 9,414,000
Net Income (Loss) Allocated to Limited Partners									8,123,000
Net Income (Loss) Allocated to General Partners						219,211,000
Issuance of units						(264,000)	(264,000)			1,482,000
Units repurchased and retired						(2,921,000)	(2,921,000)
Exercise of unit options						916,000	916,000
General partnership units issued in exchange for limited partnership units						4,444,000	0		(4,444,000)
Partnership units issued in exchange for redeemable units						1,915,000	1,915,000			$ (1,915,000)
Distributions						(424,302,000)	(439,461,000)		$ (15,159,000)
Partners' Capital at Dec. 31, 2018					$ 220,043,000	$ 6,083,142,000	$ 6,372,170,000	$ (161,000)			$ 66,840,000
Dividends on noncontrolling interest units														$ 0					$ (15,159,000)				$ (15,159,000)
Distribution Made to Limited Partner, Distributions Declared, Per Unit				$ 3.7275
Preferred Stock, Shares Outstanding												867,846		868,000
Preferred Stock, Value, Outstanding												$ 9,000		$ 9,000
Noncontrolling Interest in Joint Ventures				$ 2,306,000								$ 2,306,000