Consolidated Statements of Changes in Equity - USD ($) $ in Thousands	Total	Series A Cumulative Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in-Capital	Retained Earnings (Distributions in excess of net earnings)	Accumulated Other Comprehensive Income	Operating Partnership	Consolidated Joint Venture	Preferred Capital in Consolidated Joint Venture [Member]
Balance (in shares) at Dec. 31, 2017		12,879,475	174,869,046
Balance at Dec. 31, 2017	$ 3,570,278	$ 366,936	$ 1,749	$ 3,208,002	$ (82,566)	$ 8,846	$ 11,181	$ 11,700	$ 44,430
Increase (Decrease) in Owners' Equity
Net Income (Loss) Attributable to Parent	161,378				161,378
Net income (loss)	162,943						626	(170)	1,109
Unrealized loss on interest rate derivatives	29,469					29,469
Reclassification of unrealized gain on discontinued cash flow hedges to interest expense	0
Contributions from a noncontrolling interest	110							110
Issuance of restricted stock (in shares)			591,851
Issuance of restricted stock	0		$ 6	(6)
Amortization of share-based compensation	10,135			10,135
Shares acquired to satisfy minimum required federal and state tax withholding on vesting restricted stock (in shares)			(132,370)
Shares acquired to satisfy minimum required federal and state tax withholding on vesting restricted stock	(2,926)		$ (2)	(2,924)
Forfeiture of restricted stock (in shares)			(113,325)
Forfeiture of restricted stock	0		$ (1)	1
Dividends, Preferred Stock	(18,836)				(18,836)
Distributions on common shares and units	(174,600)				(173,817)		(783)
Preferred distributions - consolidated joint venture	(1,109)								(1,109)
Balance (in shares) at Sep. 30, 2018		12,879,475	175,215,202
Balance at Sep. 30, 2018	3,575,464	$ 366,936	$ 1,752	3,215,208	(113,841)	38,315	11,024	11,640	44,430
Balance (in shares) at Jun. 30, 2018		12,879,475	175,278,298
Balance at Jun. 30, 2018	3,558,569	$ 366,936	$ 1,753	3,213,049	(123,809)	33,640	10,975	11,595	44,430
Increase (Decrease) in Owners' Equity
Net Income (Loss) Attributable to Parent	73,975				73,975
Net income (loss)	74,657						299	9	374
Unrealized loss on interest rate derivatives	4,675					4,675
Reclassification of unrealized gain on discontinued cash flow hedges to interest expense	0
Contributions from a noncontrolling interest	36							36
Issuance of restricted stock (in shares)			133,644
Issuance of restricted stock	0		$ 1	(1)
Amortization of share-based compensation	4,085			4,085
Shares acquired to satisfy minimum required federal and state tax withholding on vesting restricted stock (in shares)			(86,898)
Shares acquired to satisfy minimum required federal and state tax withholding on vesting restricted stock	(1,927)		$ (1)	(1,926)
Forfeiture of restricted stock (in shares)			(109,842)
Forfeiture of restricted stock	0		$ (1)	1
Dividends, Preferred Stock	(6,279)				(6,279)
Distributions on common shares and units	(57,978)				(57,728)		(250)
Preferred distributions - consolidated joint venture	(374)								(374)
Balance (in shares) at Sep. 30, 2018		12,879,475	175,215,202
Balance at Sep. 30, 2018	3,575,464	$ 366,936	$ 1,752	3,215,208	(113,841)	38,315	11,024	11,640	44,430
Balance (in shares) at Dec. 31, 2018		12,879,475	174,019,616
Balance at Dec. 31, 2018	3,496,941	$ 366,936	$ 1,740	3,195,381	(150,476)	16,195	10,827	11,908	44,430
Increase (Decrease) in Owners' Equity
Net Income (Loss) Attributable to Parent	93,160
Net income (loss)	94,468						329	(360)	1,339
Unrealized loss on interest rate derivatives	(41,460)					(41,460)
Reclassification of unrealized gain on discontinued cash flow hedges to interest expense	(2,250)					(2,250)
Redemption of Operating Partnership units	(9)						(9)
Contributions from a noncontrolling interest	2,446							2,446
Issuance of restricted stock (in shares)			530,436
Issuance of restricted stock	0		$ 5	(5)
Amortization of share-based compensation	9,249			9,249
Shares acquired to satisfy minimum required federal and state tax withholding on vesting restricted stock (in shares)			(73,046)
Shares acquired to satisfy minimum required federal and state tax withholding on vesting restricted stock	$ (1,293)		$ (1)	(1,292)
Shares acquired as part of a share repurchase program (in shares)	(3,836,582)		(3,836,582)
Shares acquired as part of a share repurchase program	$ (65,635)		$ (38)	(65,597)
Forfeiture of restricted stock (in shares)			(8,060)
Forfeiture of restricted stock	0		$ 0	0
Dividends, Preferred Stock	(18,836)				(18,836)
Distributions on common shares and units	(171,641)				(170,762)		(879)
Preferred distributions - consolidated joint venture	(186)								(186)
Redemption of preferred equity - consolidated joint venture	(45,583)								(45,583)
Balance (in shares) at Sep. 30, 2019		12,879,475	170,632,364
Balance at Sep. 30, 2019	3,256,211	$ 366,936	$ 1,706	3,137,736	(246,914)	(27,515)	10,268	13,994	0
Balance (in shares) at Jun. 30, 2019		12,879,475	173,459,015
Balance at Jun. 30, 2019	3,337,001	$ 366,936	$ 1,735	3,182,351	(216,583)	(21,836)	10,441	13,957	0
Increase (Decrease) in Owners' Equity
Net Income (Loss) Attributable to Parent	32,463
Net income (loss)	32,455						96	(104)	0
Unrealized loss on interest rate derivatives	(5,679)					(5,679)
Reclassification of unrealized gain on discontinued cash flow hedges to interest expense	0
Contributions from a noncontrolling interest	141							141
Amortization of share-based compensation	3,217			3,217
Shares acquired to satisfy minimum required federal and state tax withholding on vesting restricted stock (in shares)			(38,166)
Shares acquired to satisfy minimum required federal and state tax withholding on vesting restricted stock	(636)		$ 0	(636)
Shares acquired as part of a share repurchase program (in shares)			(2,787,367)
Shares acquired as part of a share repurchase program	(47,225)		$ (29)	(47,196)
Forfeiture of restricted stock (in shares)			(1,118)
Forfeiture of restricted stock	0		$ 0	0
Dividends, Preferred Stock	(6,279)				(6,279)
Distributions on common shares and units	(56,784)				(56,515)		(269)
Preferred distributions - consolidated joint venture	0
Balance (in shares) at Sep. 30, 2019		12,879,475	170,632,364
Balance at Sep. 30, 2019	$ 3,256,211	$ 366,936	$ 1,706	$ 3,137,736	$ (246,914)	$ (27,515)	$ 10,268	$ 13,994	$ 0