Consolidated Statement of Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In-Capital	Treasury Stock	Accumulated Other Comprehensive Loss	Retained Earnings	Noncontrolling Interests	Series I Preferred Stock Preferred Stock	Cumulative Effect, Period Of Adoption, Adjustment	Cumulative Effect, Period Of Adoption, Adjustment Retained Earnings	Cumulative Effect, Period Of Adoption, Adjusted Balance	Cumulative Effect, Period Of Adoption, Adjusted Balance Common Stock	Cumulative Effect, Period Of Adoption, Adjusted Balance Additional Paid-In-Capital	Cumulative Effect, Period Of Adoption, Adjusted Balance Treasury Stock	Cumulative Effect, Period Of Adoption, Adjusted Balance Accumulated Other Comprehensive Loss	Cumulative Effect, Period Of Adoption, Adjusted Balance Retained Earnings	Cumulative Effect, Period Of Adoption, Adjusted Balance Noncontrolling Interests	Cumulative Effect, Period Of Adoption, Adjusted Balance Series I Preferred Stock Preferred Stock
Beginning Balance at Dec. 31, 2018	$ 5,947,855	$ 847	$ 4,508,685	$ (124,049)	$ 15,108	$ 1,278,998	$ 46,334	$ 221,932
Beginning Balance (in shares) at Dec. 31, 2018		83,684
Increase (Decrease) in Stockholders' Equity
Net income (loss)	210,470					212,370	(1,900)
Acquisition of subsidiary interest from noncontrolling interest	(25,791)		(515)				(25,276)
Other comprehensive loss	(43,503)				(43,503)
Preferred dividends	(7,475)					(7,475)
DRSPP proceeds (in shares)		3
DRSPP proceeds	263		263
Conversion of units of the Operating Partnership to common stock (in shares)		5
Conversion of units in the Operating Partnership for common stock	446		446
Reallocation of noncontrolling interest in the Operating Partnership	(14,028)					(14,028)
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings (in shares)		(17)
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings	10,533		10,533
Repurchases of common stock (in shares)		(1,265)
Repurchases of common stock	(109,313)	$ (12)	(68,203)			(41,098)
Contributions to consolidated joint venture interests	50,692						50,692
Cash distributions to noncontrolling interests	(271)						(271)
Cash distributions declared (per common share, none of which represented a return of capital for federal income tax purposes)	(140,377)					(140,377)
Ending Balance at Jun. 30, 2019	5,879,501	$ 835	4,451,209	(124,049)	(28,395)	1,288,390	69,579	221,932
Ending Balance (in shares) at Jun. 30, 2019		82,410
Beginning Balance at Dec. 31, 2018	5,947,855	$ 847	4,508,685	(124,049)	15,108	1,278,998	46,334	221,932
Beginning Balance (in shares) at Dec. 31, 2018		83,684
Increase (Decrease) in Stockholders' Equity
Preferred dividends	(11,213)
Ending Balance at Sep. 30, 2019	5,763,300	$ 826	4,407,667	(124,049)	(40,132)	1,225,904	71,152	221,932
Ending Balance (in shares) at Sep. 30, 2019		81,515
Beginning Balance at Dec. 31, 2018	5,947,855	$ 847	4,508,685	(124,049)	15,108	1,278,998	46,334	221,932
Beginning Balance (in shares) at Dec. 31, 2018		83,684
Ending Balance at Dec. 31, 2019	5,517,198	$ 803	4,286,395	(124,049)	(28,485)	1,084,719	75,883	221,932			$ 5,478,014	$ 803	$ 4,286,395	$ (124,049)	$ (28,485)	$ 1,045,535	$ 75,883	$ 221,932
Ending Balance (Accounting Standards Update 2016-13) at Dec. 31, 2019									$ (39,184)	$ (39,184)
Ending Balance (in shares) at Dec. 31, 2019		79,202										79,202
Beginning Balance at Jun. 30, 2019	5,879,501	$ 835	4,451,209	(124,049)	(28,395)	1,288,390	69,579	221,932
Beginning Balance (in shares) at Jun. 30, 2019		82,410
Increase (Decrease) in Stockholders' Equity
Net income (loss)	36,271					36,895	(624)
Acquisition of subsidiary interest from noncontrolling interest	(54)		(54)
Other comprehensive loss	(11,737)				(11,737)
Preferred dividends	(3,738)					(3,738)
DRSPP proceeds (in shares)
DRSPP proceeds	39		39
Conversion of units in the Operating Partnership for common stock	25		25
Reallocation of noncontrolling interest in the Operating Partnership	(1,481)					(1,481)
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings (in shares)		21
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings	5,948		5,948
Repurchases of common stock (in shares)		(916)
Repurchases of common stock	(74,531)	$ (9)	(49,500)			(25,022)
Contributions to consolidated joint venture interests	2,404						2,404
Cash distributions to noncontrolling interests	(207)						(207)
Cash distributions declared (per common share, none of which represented a return of capital for federal income tax purposes)	(69,140)					(69,140)
Ending Balance at Sep. 30, 2019	$ 5,763,300	$ 826	4,407,667	(124,049)	(40,132)	1,225,904	71,152	221,932
Ending Balance (in shares) at Sep. 30, 2019		81,515
Increase (Decrease) in Stockholders' Equity
Cash distribution declared, per common share (in dollars per share)	$ 0.85
Beginning Balance at Dec. 31, 2019	$ 5,517,198	$ 803	4,286,395	(124,049)	(28,485)	1,084,719	75,883	221,932			5,478,014	$ 803	4,286,395	(124,049)	(28,485)	1,045,535	75,883	221,932
Beginning Balance (in shares) at Dec. 31, 2019		79,202										79,202
Increase (Decrease) in Stockholders' Equity
Net income (loss)	179,451					178,720	731
Acquisition of subsidiary interest from noncontrolling interest	(1,536)		(3,123)				1,587
Other comprehensive loss	(53,886)				(53,886)
Preferred dividends	(7,475)					(7,475)
DRSPP proceeds (in shares)		6
DRSPP proceeds	364		364
Conversion of units of the Operating Partnership to common stock (in shares)		101
Conversion of units in the Operating Partnership for common stock	8,744	$ 1	8,743
Reallocation of noncontrolling interest in the Operating Partnership	31,144					31,144
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings (in shares)		(33)
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings	13,493		13,493
Repurchases of common stock (in shares)		(5,601)
Repurchases of common stock	(360,868)	$ (56)	(283,981)			(76,831)
Contributions to consolidated joint venture interests	8,185						8,185
Cash distributions to noncontrolling interests	(596)						(596)
Cash distributions declared (per common share, none of which represented a return of capital for federal income tax purposes)	(89,272)					(89,272)
Ending Balance at Jun. 30, 2020	5,205,762	$ 748	4,021,891	(124,049)	(82,371)	1,081,821	85,790	221,932
Ending Balance (in shares) at Jun. 30, 2020		73,675
Beginning Balance at Dec. 31, 2019	5,517,198	$ 803	4,286,395	(124,049)	(28,485)	1,084,719	75,883	221,932			$ 5,478,014	$ 803	$ 4,286,395	$ (124,049)	$ (28,485)	$ 1,045,535	$ 75,883	$ 221,932
Beginning Balance (Accounting Standards Update 2016-13) at Dec. 31, 2019									$ (39,184)	$ (39,184)
Beginning Balance (in shares) at Dec. 31, 2019		79,202										79,202
Increase (Decrease) in Stockholders' Equity
Preferred dividends	(11,213)
Ending Balance at Sep. 30, 2020	5,134,005	$ 741	3,998,516	(124,049)	(76,200)	1,035,172	77,893	221,932
Ending Balance (in shares) at Sep. 30, 2020		73,040
Beginning Balance at Jun. 30, 2020	5,205,762	$ 748	4,021,891	(124,049)	(82,371)	1,081,821	85,790	221,932
Beginning Balance (in shares) at Jun. 30, 2020		73,675
Increase (Decrease) in Stockholders' Equity
Net income (loss)	18,011					17,597	414
Acquisition of subsidiary interest from noncontrolling interest	0		0				0
Other comprehensive loss	6,171				6,171
Preferred dividends	(3,738)					(3,738)
DRSPP proceeds (in shares)		4
DRSPP proceeds	202		202
Conversion of units of the Operating Partnership to common stock (in shares)		0
Conversion of units in the Operating Partnership for common stock	0	$ 0	0
Reallocation of noncontrolling interest in the Operating Partnership	4,109					4,109
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings (in shares)		3
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings	7,543	$ 0	7,543
Repurchases of common stock (in shares)		(642)
Repurchases of common stock	(31,127)	$ (7)	(31,120)			0
Contributions to consolidated joint venture interests	4,219						4,219
Cash distributions to noncontrolling interests	(12,530)						(12,530)
Cash distributions declared (per common share, none of which represented a return of capital for federal income tax purposes)	(64,617)					(64,617)
Ending Balance at Sep. 30, 2020	$ 5,134,005	$ 741	$ 3,998,516	$ (124,049)	$ (76,200)	$ 1,035,172	$ 77,893	$ 221,932
Ending Balance (in shares) at Sep. 30, 2020		73,040
Increase (Decrease) in Stockholders' Equity
Cash distribution declared, per common share (in dollars per share)	$ 0.885