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, 2013		5,750,000	38,788,745
Beginning balance at Dec. 31, 2013	$ 460,164	$ 58	$ 388	$ 534,639	$ (74,921)	$ 0	$ 460,164	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	7,475				7,498		7,498	(23)
Amortization of stock-based compensation	5,195			5,195			5,195
Common stock issuance, net (in shares)										8,474,406
Common stock issuance, net									$ 220,509	$ 85	$ 220,424	$ 220,509
Preferred dividends	(5,121)				(5,121)		(5,121)
Common dividends	(32,407)				(32,407)		(32,407)
Ending balance (in shares) at Jun. 30, 2014		5,750,000	47,263,151
Ending balance at Jun. 30, 2014	655,815	$ 58	$ 473	760,258	(104,951)	0	655,838	(23)
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)