Condensed Consolidated Statements of Changes in Equity (Unaudited) - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Retained Earnings (Deficit) and Distributions	Total Stockholders’ Equity	Non-controlling Interests in Operating Partnership
Balance at beginning of year at Dec. 31, 2015	$ 856,926	$ 84	$ 868	$ 894,060	$ (1,666)	$ (40,635)	$ 852,711	$ 4,215
Balance (in shares) at Dec. 31, 2015		8,400,000	86,793,521
Changes in equity
Net proceeds from sale of common and preferred stock	$ 72,290	$ 30		72,260			72,290
Net proceeds from sale of common and preferred stock (in shares)	0	3,000,000
Common stock redemption of common units			$ 1	510			511	(511)
Common stock redemption of common units (in shares)	61,056		61,056
Dividends	$ (47,506)					(47,328)	(47,328)	(178)
Equity-based compensation	3,202		$ 5	3,180			3,185	17
Equity-based compensation (in shares)			521,995
Shares acquired to satisfy employee withholding requirements	$ (1,265)		$ (1)	(1,264)			(1,265)
Shares acquired to satisfy employee withholding requirements (in shares)	(61,622)		(61,622)
Other comprehensive income	$ (102)				(101)		(101)	(1)
Net income	97,887					97,433	97,433	454
Balance at end of year at Sep. 30, 2016	981,432	$ 114	$ 873	968,746	(1,767)	9,470	977,436	3,996
Balance (in shares) at Sep. 30, 2016		11,400,000	87,314,950
Balance at beginning of year at Dec. 31, 2016	1,013,470	$ 94	$ 935	1,011,412	(977)	(1,422)	1,010,042	3,428
Balance (in shares) at Dec. 31, 2016		9,400,000	93,525,469
Changes in equity
Net proceeds from sale of common and preferred stock	$ 163,620		$ 104	163,516			163,620
Net proceeds from sale of common and preferred stock (in shares)	10,350,000		10,350,000
Common stock redemption of common units			$ 1	466			467	(467)
Common stock redemption of common units (in shares)	52,808		52,808
Dividends	$ (63,424)					(63,240)	(63,240)	(184)
Equity-based compensation	4,483		$ 4	4,462			4,466	17
Equity-based compensation (in shares)			397,421
Shares acquired to satisfy employee withholding requirements	$ (961)		$ (1)	(960)			(961)
Shares acquired to satisfy employee withholding requirements (in shares)	(59,111)		(59,111)
Other comprehensive income	$ 680				677		677	3
Net income	89,734					89,445	89,445	289
Balance at end of year at Sep. 30, 2017	$ 1,207,602	$ 94	$ 1,043	$ 1,178,896	$ (300)	$ 24,783	$ 1,204,516	$ 3,086
Balance (in shares) at Sep. 30, 2017		9,400,000	104,266,587