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	$ (1,679)	$ 1,548	$ 200,000	$ 6,294,719	$ (760,523)	$ (1,505)	$ (2,722)	$ (48,335)	$ 600,860	$ (174)	$ 1,728,689
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Redemption of operating partnership units to common stock, shares			462,000
Redemption of operating partnership units to common stock, value	0		$ 5		15,490					(15,495)
Allocated net income for the year	577,146					500,121				57,539		19,486
Dividends/distributions declared	(172,277)					(154,833)				(17,444)
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			61,000
Net activity from stock option and incentive plan, value	23,060				7,383					15,677
Preferred Stock Redemption Charge	0
Contributions from noncontrolling interests in property partnerships	3,876											3,876
Distributions to noncontrolling interests in property partnerships	(15,750)											(15,750)
Effective portion of interest rate contracts	(9,720)								(8,732)	(988)
Amortization of interest rate contracts	1,666								1,367	155		144
Reallocation of noncontrolling interest	0				3,558					(3,558)
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]
Accounting Standards Update [Extensible List] | Accounting Standards Update 2018-09	Accounting Standards Update 2018-09
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			118,000
Redemption of operating partnership units to common stock, value	0		$ 1		4,197					(4,198)
Allocated net income for the year	128,147					100,596				11,084		16,467
Dividends/distributions declared	(172,800)					(155,513)				(17,287)
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			232,000
Net activity from stock option and incentive plan, value	38,467		$ 3		20,002					18,462
Preferred Stock Redemption Charge	(6,412)					(6,412)
Contributions from noncontrolling interests in property partnerships	281											281
Distributions to noncontrolling interests in property partnerships	(18,225)											(18,225)
Effective portion of interest rate contracts	3,740								3,370	370		0
Amortization of interest rate contracts	1,676								1,381	151		144
Reallocation of noncontrolling interest	$ 0				5,072					(5,072)
Equity, shares at Mar. 31, 2021	156,074,200		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]
Preferred Stock, Redemption Amount	$ (193,623)			$ (200,000)	$ (6,377)