Condensed Consolidated Statements of Equity (unaudited) - USD ($) $ in Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Cumulative Distributions in Excess of Net Income [Member]	Accumulated Other Comprehensive Loss [Member]	Total Stockholders' Equity [Member]	Noncontrolling Interest [Member]	Common Stock [Member]	Common Stock [Member] Common Stock [Member]	Common Stock [Member] Additional Paid-in Capital [Member]	Common Stock [Member] Total Stockholders' Equity [Member]
Beginning balance (in shares) at Dec. 31, 2014		5,750,000	59,047,001
Beginning balance at Dec. 31, 2014	$ 941,823	$ 58	$ 590	$ 1,053,601	$ (110,841)	$ (1,542)	$ 941,866	$ (43)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	36,265				36,285		36,285	(20)
Other comprehensive loss	(3,284)					(3,284)	(3,284)
Amortization of stock-based compensation	4,940			4,940			4,940
Common stock issuance, net (in shares)										6,087,055
Common stock issuance, net									$ 142,675	$ 61	$ 142,614	$ 142,675
Preferred dividends	(5,121)				(5,121)		(5,121)
Common dividends	(46,490)				(46,490)		(46,490)
Ending balance (in shares) at Jun. 30, 2015		5,750,000	65,134,056
Ending balance at Jun. 30, 2015	1,070,808	$ 58	$ 651	1,201,155	(126,167)	(4,826)	1,070,871	(63)
Beginning balance (in shares) at Dec. 31, 2015		5,750,000	65,182,335
Beginning balance at Dec. 31, 2015	1,053,876	$ 58	$ 652	1,202,541	(142,148)	(7,333)	1,053,770	106
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	21,723				21,764		21,764	(41)
Other comprehensive loss	(1,947)					(1,947)	(1,947)
Amortization of stock-based compensation	3,982			3,982			3,982
Common stock issuance, net (in shares)										105,981
Common stock issuance, net									$ (1,103)	$ 1	$ (1,104)	$ (1,103)
Preferred dividends	(5,121)				(5,121)		(5,121)
Common dividends	(54,498)				(54,498)		(54,498)
Ending balance (in shares) at Jun. 30, 2016		5,750,000	65,288,316.000
Ending balance at Jun. 30, 2016	$ 1,016,912	$ 58	$ 653	$ 1,205,419	$ (180,003)	$ (9,280)	$ 1,016,847	$ 65