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)	19,439				19,450		19,450	(11)
Other comprehensive loss	(1,545)					(1,545)	(1,545)
Amortization of stock-based compensation	3,023			3,023			3,023
Common stock issuance, net (in shares)										187,055
Common stock issuance, net									$ (4,809)	$ 2	$ (4,811)	$ (4,809)
Preferred dividends	(2,561)				(2,561)		(2,561)
Common dividends	(23,216)				(23,216)		(23,216)
Ending balance (in shares) at Mar. 31, 2015		5,750,000	59,234,056
Ending balance at Mar. 31, 2015	932,154	$ 58	$ 592	1,051,813	(117,168)	(3,087)	932,208	(54)
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)	(15,743)				(15,711)			(32)
Other comprehensive loss	(2,065)					(2,065)	(2,065)
Amortization of stock-based compensation	1,938			1,938			1,938
Common stock issuance, net (in shares)										90,883
Common stock issuance, net									$ (1,088)	$ 1	$ (1,089)	$ (1,088)
Preferred dividends	(2,561)				(2,561)		(2,561)
Common dividends	(26,859)				(26,859)		(26,859)
Ending balance (in shares) at Mar. 31, 2016		5,750,000	65,273,218.000
Ending balance at Mar. 31, 2016	$ 1,007,498	$ 58	$ 653	$ 1,203,390	$ (187,279)	$ (9,398)	$ 1,007,424	$ 74