Consolidated Statements Of Equity - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock [Member]	Preferred Stock [Member]	Additional Paid-In Capital [Member]	Dividends In Excess Of Earnings [Member]	Dividends In Excess Of Earnings [Member] Cumulative Effect, Period of Adoption, Adjustment	Treasury Stock, at cost [Member]	Accumulated Other Comprehensive Loss [Member]	Noncontrolling Interests [Member]	Noncontrolling Interests [Member] Cumulative Effect, Period of Adoption, Adjustment	Noncontrolling interest - property partnerships [Member]
Equity, shares at Dec. 31, 2019			154,790,000
Equity, value at Dec. 31, 2019	$ 8,014,236		$ 1,548	$ 200,000	$ 6,294,719	$ (760,523)		$ (2,722)	$ (48,335)	$ 600,860		$ 1,728,689
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible List] | Accounting Standards Update 2018-09	Accounting Standards Update 2018-09
Redemption of operating partnership units to common stock, shares			765,000
Redemption of operating partnership units to common stock, value	$ 0		$ 8		26,336					(26,344)
Allocated net income for the year	875,726					769,482				87,525		18,719
Dividends/distributions declared	(344,603)					(309,965)				(34,638)
Shares issued pursuant to stock purchase plan, shares			2,000
Shares issued pursuant to stock purchase plan, value	325				325
Net activity from stock option and incentive plan, shares			65,000
Net activity from stock option and incentive plan, value	33,285		$ 0		8,256					25,029
Preferred Stock Redemption Charge	0
Contributions from noncontrolling interests in property partnerships	5,957											5,957
Distributions to noncontrolling interests in property partnerships	(29,065)											(29,065)
Effective portion of interest rate contracts	(10,379)								(9,333)	(1,046)		0
Amortization of interest rate contracts	3,343								2,747	308		288
Reallocation of noncontrolling interest	0				11,029					(11,029)
Equity, shares at Jun. 30, 2020			155,622,000
Equity, value at Jun. 30, 2020	8,547,146	$ (1,679)	$ 1,556	200,000	6,340,665	(302,511)	$ (1,505)	(2,722)	(54,921)	640,491	$ (174)	1,724,588
Equity, shares at Mar. 31, 2020			155,315,000
Equity, value at Mar. 31, 2020	8,420,883		$ 1,553	200,000	6,321,475	(416,740)		(2,722)	(55,700)	636,572		1,736,445
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Redemption of operating partnership units to common stock, shares			303,000
Redemption of operating partnership units to common stock, value	0		$ 3		10,846					(10,849)
Allocated net income for the year	298,580					269,361				29,986		(767)
Dividends/distributions declared	(172,326)					(155,132)				(17,194)
Net activity from stock option and incentive plan, shares			4,000
Net activity from stock option and incentive plan, value	10,225				873					9,352
Preferred Stock Redemption Charge	0
Contributions from noncontrolling interests in property partnerships	2,081											2,081
Distributions to noncontrolling interests in property partnerships	(13,315)											(13,315)
Effective portion of interest rate contracts	(659)								(601)	(58)
Amortization of interest rate contracts	1,677								1,380	153		144
Reallocation of noncontrolling interest	0				7,471					(7,471)
Equity, shares at Jun. 30, 2020			155,622,000
Equity, value at Jun. 30, 2020	$ 8,547,146	$ (1,679)	$ 1,556	200,000	6,340,665	(302,511)	$ (1,505)	(2,722)	(54,921)	640,491	$ (174)	1,724,588
Equity, shares at Dec. 31, 2020	155,718,825		155,719,000
Equity, value at Dec. 31, 2020	$ 8,339,612		$ 1,557	200,000	6,356,791	(509,653)		(2,722)	(49,890)	616,596		1,726,933
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Redemption of operating partnership units to common stock, shares			177,000
Redemption of operating partnership units to common stock, value	0		$ 1		6,284					(6,285)
Allocated net income for the year	269,397					212,344				23,422		33,631
Dividends/distributions declared	(343,066)					(308,526)				(34,540)
Shares issued pursuant to stock purchase plan, shares			5,000
Shares issued pursuant to stock purchase plan, value	484				484
Net activity from stock option and incentive plan, shares			235,000
Net activity from stock option and incentive plan, value	51,364		$ 3		19,708					31,653
Preferred Stock, Redeemed	(193,623)			(200,000)	6,377
Preferred Stock Redemption Charge	(6,412)					6,412
Contributions from noncontrolling interests in property partnerships	2,420											2,420
Distributions to noncontrolling interests in property partnerships	(37,929)											(37,929)
Effective portion of interest rate contracts	(4,394)								3,962	(432)
Amortization of interest rate contracts	3,352								2,762	302		288
Reallocation of noncontrolling interest	$ 0				16,272					(16,272)
Equity, shares at Jun. 30, 2021	156,135,959		156,136,000
Equity, value at Jun. 30, 2021	$ 8,089,993		$ 1,561	0	6,405,916	(612,247)		(2,722)	(43,166)	615,308		1,725,343
Equity, shares at Mar. 31, 2021			156,074,000
Equity, value at Mar. 31, 2021	8,121,347		$ 1,561	0	6,392,923	(570,982)		(2,722)	(45,139)	620,106		1,725,600
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Redemption of operating partnership units to common stock, shares			59,000
Redemption of operating partnership units to common stock, value	0		$ 0		2,087					(2,087)
Allocated net income for the year	141,250					111,748				12,338		17,164
Dividends/distributions declared	(170,266)					(153,013)				(17,253)
Net activity from stock option and incentive plan, shares			3,000
Net activity from stock option and incentive plan, value	12,897		$ 0		(294)					13,191
Preferred Stock Redemption Charge	0
Contributions from noncontrolling interests in property partnerships	2,139											2,139
Distributions to noncontrolling interests in property partnerships	(19,704)											(19,704)
Effective portion of interest rate contracts	654								593	61		0
Amortization of interest rate contracts	1,676								1,380	152		144
Reallocation of noncontrolling interest	$ 0				11,200					(11,200)
Equity, shares at Jun. 30, 2021	156,135,959		156,136,000
Equity, value at Jun. 30, 2021	$ 8,089,993		$ 1,561	$ 0	$ 6,405,916	$ (612,247)		$ (2,722)	$ (43,166)	$ 615,308		$ 1,725,343