Consolidated Statement of Equity - 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, 2019	$ 5,517,198	$ 803	$ 4,286,395	$ (124,049)	$ (28,485)	$ 1,084,719	$ 75,883	$ 221,932	$ (39,184)	$ (39,184)	$ 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		76,956										76,956
Increase (Decrease) in Stockholders' Equity
Net income (loss)	179,450					178,720	730
Acquisition of subsidiary interest from noncontrolling interest	(1,536)		(3,123)				1,587
Other comprehensive income (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)		98
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)		(32)
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings	13,493		13,493
Repurchases of common stock (in shares)		(5,442)
Repurchases of common stock	(360,868)	$ (56)	(283,981)			(76,831)
Contributions to consolidated joint venture interests	8,186						8,186
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		71,586
Beginning Balance at Dec. 31, 2019	5,517,198	$ 803	4,286,395	(124,049)	(28,485)	1,084,719	75,883	221,932	(39,184)	(39,184)	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		76,956										76,956
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		70,969
Beginning Balance at Dec. 31, 2019	5,517,198	$ 803	4,286,395	(124,049)	(28,485)	1,084,719	75,883	221,932	$ (39,184)	$ (39,184)	$ 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		76,956										76,956
Ending Balance at Dec. 31, 2020	4,935,795	$ 716	3,862,949	(124,049)	(67,247)	1,015,462	26,032	221,932
Ending Balance (in shares) at Dec. 31, 2020		68,508
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		71,586
Increase (Decrease) in Stockholders' Equity
Net income (loss)	18,011					17,597	414
Other comprehensive income (loss)	6,171				6,171
Preferred dividends	(3,738)					(3,738)
DRSPP proceeds (in shares)		4
DRSPP proceeds	202		202
Conversion of units in the Operating Partnership for common stock	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		7,543
Repurchases of common stock (in shares)		(624)
Repurchases of common stock	(31,127)	$ (7)	(31,120)
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		70,969
Beginning Balance at Dec. 31, 2020	4,935,795	$ 716	3,862,949	(124,049)	(67,247)	1,015,462	26,032	221,932
Beginning Balance (in shares) at Dec. 31, 2020		68,508
Increase (Decrease) in Stockholders' Equity
Net income (loss)	103,804					105,343	(1,539)
Other comprehensive income (loss)	384				384
Preferred dividends	(7,475)					(7,475)
DRSPP proceeds (in shares)		7
DRSPP proceeds	467		467
Reallocation of noncontrolling interest in the Operating Partnership	(32,475)					(32,475)
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings (in shares)		112
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings	14,319	$ 2	14,317
Repurchases of common stock (in shares)		(2,781)
Repurchases of common stock	(198,887)	$ (28)	(177,972)			(20,887)
Contributions to consolidated joint venture interests	305						305
Cash distributions to noncontrolling interests	(173)						(173)
Issuance of special dividend paid primarily in stock (in shares)		2,034
Issuance of special dividend paid primarily in stock	123,529		123,529
Cash distributions declared (per common share, none of which represented a return of capital for federal income tax purposes)	(125,836)					(125,836)
Ending Balance at Jun. 30, 2021	4,813,757	$ 690	3,823,290	(124,049)	(66,863)	934,132	24,625	221,932
Ending Balance (in shares) at Jun. 30, 2021		67,880
Beginning Balance at Dec. 31, 2020	4,935,795	$ 716	3,862,949	(124,049)	(67,247)	1,015,462	26,032	221,932
Beginning Balance (in shares) at Dec. 31, 2020		68,508
Increase (Decrease) in Stockholders' Equity
Preferred dividends	(11,213)
Ending Balance at Sep. 30, 2021	5,082,215	$ 680	3,774,119	(126,160)	(60,597)	1,258,232	14,009	221,932
Ending Balance (in shares) at Sep. 30, 2021		66,865
Beginning Balance at Jun. 30, 2021	4,813,757	$ 690	3,823,290	(124,049)	(66,863)	934,132	24,625	221,932
Beginning Balance (in shares) at Jun. 30, 2021		67,880
Increase (Decrease) in Stockholders' Equity
Net income (loss)	391,028					391,943	(915)
Other comprehensive income (loss)	6,266				6,266
Preferred dividends	(3,738)					(3,738)
DRSPP proceeds (in shares)		2
DRSPP proceeds	146		146
Reallocation of noncontrolling interest in the Operating Partnership	15,230					15,230
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings (in shares)		(1)
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings	7,932		7,932
Repurchases of common stock (in shares)		(1,016)
Repurchases of common stock	(77,957)	$ (10)	(57,249)			(20,698)
Contributions to consolidated joint venture interests	5						5
Sale of interest in partially owned entity	(4,476)						(4,476)
Cash distributions to noncontrolling interests	(5,230)						(5,230)
Issuance of special dividend paid primarily in stock	0			(2,111)		2,111
Cash distributions declared (per common share, none of which represented a return of capital for federal income tax purposes)	(60,748)					(60,748)
Ending Balance at Sep. 30, 2021	$ 5,082,215	$ 680	$ 3,774,119	$ (126,160)	$ (60,597)	$ 1,258,232	$ 14,009	$ 221,932
Ending Balance (in shares) at Sep. 30, 2021		66,865