Consolidated Statement of Changes in Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Distributions in Excess of Net Income [Member]	Total Stockholders' Equity [Member]	Noncontrolling Interest Exchangeable Operating Partnership Units [Member]	Noncontrolling Interests in Limited Partners' Interest in Consolidated Partnerships [Member]	Noncontrolling Interest [Member]
Beginning balance at Dec. 31, 2018	$ 6,450,168	$ 1,679	$ (19,834)	$ 7,672,517	$ (927)	$ (1,255,465)	$ 6,397,970	$ 10,666	$ 41,532	$ 52,198
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	91,493					90,446	90,446	190	857	1,047
Other comprehensive (loss) income:
Other comprehensive loss before reclassification	(5,352)				(5,017)		(5,017)	(10)	(325)	(335)
Amounts reclassified from accumulated other comprehensive loss	(176)				(152)		(152)	(1)	(23)	(24)
Deferred compensation plan, net	0		(1,392)	1,392
Restricted stock issued, net of amortization	3,952	2		3,950			3,952
Common stock redeemed for taxes withheld for stock based compensation, net	(6,051)			(6,051)			(6,051)
Common stock repurchased and retired	(32,778)	(6)		(32,772)			(32,778)
Common stock issued under dividend reinvestment plan	383			383			383
Contributions from partners	895								895	895
Distributions to partners	(1,565)								(1,565)	(1,565)
Reallocation of limited partner's interest	0			(66)			(66)		66	66
Cash dividends declared - common stock/unit	(98,196)					(97,992)	(97,992)	(204)		(204)
Ending Balance at Mar. 31, 2019	6,402,773	1,675	(21,226)	7,639,353	(6,096)	(1,263,011)	6,350,695	10,641	41,437	52,078
Beginning balance at Dec. 31, 2019	6,289,961	1,676	(23,199)	7,654,930	(11,997)	(1,408,062)	6,213,348	36,100	40,513	76,613
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(24,783)					(25,332)	(25,332)	(115)	664	549
Other comprehensive (loss) income:
Other comprehensive loss before reclassification	(16,064)				(14,938)		(14,938)	(67)	(1,059)	(1,126)
Amounts reclassified from accumulated other comprehensive loss	1,425				1,404		1,404	6	15	21
Deferred compensation plan, net	0		(698)	698
Restricted stock issued, net of amortization	3,764	1		3,763			3,764
Common stock redeemed for taxes withheld for stock based compensation, net	(5,188)			(5,188)			(5,188)
Common stock issued under dividend reinvestment plan	379			379			379
Common stock issued, net of issuance costs	125,773	19		125,754			125,773
Contributions from partners	100								100	100
Issuance of exchangeable operating partnership units	1,275							1,275		1,275
Distributions to partners	(1,164)								(1,164)	(1,164)
Cash dividends declared - common stock/unit	(100,243)					(99,788)	(99,788)	(455)		(455)
Ending Balance at Mar. 31, 2020	$ 6,275,235	$ 1,696	$ (23,897)	$ 7,780,336	$ (25,531)	$ (1,533,182)	$ 6,199,422	$ 36,744	$ 39,069	$ 75,813