Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Preferred Shares	Common Shares	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Distributions in Excess of Retained Earnings	Total Shareholders' Equity	Non-Controlling Interests
Preferred stock, beginning balance (in shares) at Dec. 31, 2016		10,000,000
Common stock, beginning balance (in shares) at Dec. 31, 2016			71,922,904
Beginning balance at Dec. 31, 2016	$ 1,609,116	$ 100	$ 719	$ 1,776,404	$ (2,312)	$ (169,227)	$ 1,605,684	$ 3,432
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares, offering costs	(62)			(62)			(62)
Issuance of common shares for Board of Trustees compensation (in shares)			16,711
Issuance of common shares for Board of Trustees compensation	503		$ 1	502			503
Repurchase of common shares (in shares)			(3,335,278)
Repurchase of common shares	(95,981)		$ (33)	(95,948)			(95,981)
Share-based compensation (in shares)			208,238
Share-based compensation	5,646		$ 1	4,541			4,542	1,104
Distributions on common shares/units	(105,939)					(105,580)	(105,580)	(359)
Distributions on preferred shares	(16,126)					(16,094)	(16,094)	(32)
Net contribution from non-controlling interests	106							106
Other comprehensive income (loss):
Unrealized gain (loss) on derivative instruments	6,001				6,001		6,001
Net income (loss)	100,262					99,888	99,888	374
Preferred stock, ending balance (in shares) at Dec. 31, 2017		10,000,000
Common stock, ending balance (in shares) at Dec. 31, 2017			68,812,575
Ending balance at Dec. 31, 2017	1,503,526	$ 100	$ 688	1,685,437	3,689	(191,013)	1,498,901	4,625
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares, net of offering costs (in shares)		10,400,000	61,399,104
Issuance of shares, net of offering costs	2,377,807	$ 104	$ 614	2,377,089			2,377,807
Issuance of operating partnership units	4,665							4,665
Issuance of common shares for Board of Trustees compensation (in shares)			17,410
Issuance of common shares for Board of Trustees compensation	662		$ 1	661			662
Repurchase of common shares (in shares)			(69,687)
Repurchase of common shares	(2,507)		$ (1)	(2,506)			(2,507)
Share-based compensation (in shares)			151,887
Share-based compensation	6,228		$ 1	5,123			5,124	1,104
Distributions on common shares/units	(113,549)					(113,172)	(113,172)	(377)
Distributions on preferred shares	(17,505)					(17,466)	(17,466)	(39)
Net contribution from non-controlling interests	125							125
Other comprehensive income (loss):
Unrealized gain (loss) on derivative instruments	(2,907)				(2,907)		(2,907)
Net income (loss)	$ 13,385					13,393	13,393	(8)
Preferred stock, ending balance (in shares) at Dec. 31, 2018	20,400,000	20,400,000
Common stock, ending balance (in shares) at Dec. 31, 2018	130,311,289		130,311,289
Ending balance at Dec. 31, 2018	$ 3,769,930	$ 204	$ 1,303	4,065,804	1,330	(308,806)	3,759,835	10,095
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares, offering costs	(275)			(275)			(275)
Issuance of common shares for Board of Trustees compensation (in shares)			25,282
Issuance of common shares for Board of Trustees compensation	740		$ 1	739			740
Repurchase of common shares (in shares)			(126,681)
Repurchase of common shares	(4,009)		$ (1)	(4,008)			(4,009)
Share-based compensation (in shares)			275,066
Share-based compensation	8,239		$ 2	7,180			7,182	1,057
Distributions on common shares/units	(199,638)					(199,076)	(199,076)	(562)
Distributions on preferred shares	(32,606)					(32,556)	(32,556)	(50)
Redemption of non-controlling interests	(125)			(30)			(30)	(95)
Other comprehensive income (loss):
Unrealized gain (loss) on derivative instruments	(26,045)				(26,045)		(26,045)
Net income (loss)	$ 115,725					115,442	115,442	283
Preferred stock, ending balance (in shares) at Dec. 31, 2019	20,400,000	20,400,000
Common stock, ending balance (in shares) at Dec. 31, 2019	130,484,956		130,484,956
Ending balance at Dec. 31, 2019	$ 3,631,936	$ 204	$ 1,305	$ 4,069,410	$ (24,715)	$ (424,996)	$ 3,621,208	$ 10,728