Condensed Consolidated Statements of Changes in Equity (Unaudited) - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings (Deficit) and Distributions	Total Stockholders’ Equity	Non-controlling Interests in Operating Partnership
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 stock	$ 163,620		$ 104	163,516			163,620
Net proceeds from sale of common 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 for employee withholding requirements	$ (961)		$ (1)	(960)			(961)
Shares acquired for 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
Balance at beginning of year at Dec. 31, 2017	$ 1,277,376	$ 128	$ 1,043	1,262,679	1,451	9,201	1,274,502	2,874
Balance (in shares) at Dec. 31, 2017		12,800,000	104,287,128
Changes in equity
Net proceeds from sale of common stock (in shares)	0
Redemption of preferred stock	$ (85,000)	$ (34)		(81,689)		(3,277)	(85,000)
Redemption of preferred stock (in shares)		(3,400,000)
Common stock redemption of common units				227			227	(227)
Common stock redemption of common units (in shares)	25,839		25,839
Dividends	$ (69,608)					(69,441)	(69,441)	(167)
Equity-based compensation	5,367		$ 6	5,345			5,351	16
Equity-based compensation (in shares)			620,593
Shares acquired for employee withholding requirements	$ (2,724)		$ (2)	(2,722)			(2,724)
Shares acquired for employee withholding requirements (in shares)	(187,850)		(187,850)
Other	$ (146)			(146)			(146)
Other comprehensive income	6,601				6,582		6,582	19
Net income	85,369					85,165	85,165	204
Balance at end of year at Sep. 30, 2018	$ 1,217,235	$ 94	$ 1,047	$ 1,183,694	$ 8,033	$ 21,648	$ 1,214,516	$ 2,719
Balance (in shares) at Sep. 30, 2018		9,400,000	104,745,710