Condensed Consolidated Statements of Changes in Equity - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit and Distributions	Total Stockholders’ Equity	Non-controlling Interests in Operating Partnership
Balance at beginning of year at Dec. 31, 2014	$ 785,201	$ 84	$ 861	$ 888,191	$ (1,746)	$ (107,779)	$ 779,611	$ 5,590
Balance (in shares) at Dec. 31, 2014		8,400,000	86,149,720
Changes in equity
Common stock redemption of common units			$ 2	1,234			1,236	(1,236)
Common stock redemption of common units (in shares)	172,429		172,429
Dividends paid	$ (43,106)					(42,865)	(42,865)	(241)
Equity-based compensation	3,968		$ 3	3,934			3,937	31
Equity-based compensation (in shares)			309,971
Other	$ (738)			(738)			(738)
Other (in shares)	(36,385)		(36,385)
Other comprehensive loss	$ (1,038)				(1,030)		(1,030)	(8)
Net income	40,498					40,278	40,278	220
Balance at end of year at Sep. 30, 2015	784,785	$ 84	$ 866	892,621	(2,776)	(110,366)	780,429	4,356
Balance (in shares) at Sep. 30, 2015		8,400,000	86,595,735
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 preferred stock	$ 72,290	$ 30		72,260			72,290
Net proceeds from sale of preferred stock (in shares)		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 paid	$ (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
Other	$ (1,265)		$ (1)	(1,264)			(1,265)
Other (in shares)	(61,622)		(61,622)
Other comprehensive loss	$ (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