Condensed Consolidated Statements of Equity (unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	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] Additional Paid-in Capital [Member]	Common Stock [Member] Total Stockholders' Equity [Member]
Beginning balance at Dec. 31, 2013	$ 460,164	$ 58	$ 388	$ 534,639	$ (74,921)	$ 0	$ 460,164	$ 0
Beginning balance (in shares) at Dec. 31, 2013		5,750,000	38,788,745
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(7,321)				(7,303)		(7,303)	(18)
Amortization of stock-based compensation	2,689			2,689			2,689
Common stock issuance, net									(37)	3	(40)	(37)
Common stock issuance, net (in shares)										354,506
Preferred dividends	(2,561)				(2,561)		(2,561)
Common dividends	(14,211)				(14,211)		(14,211)
Ending balance at Mar. 31, 2014	438,723	58	391	537,288	(98,996)	0	438,741	(18)
Ending balance (in shares) at Mar. 31, 2014		5,750,000	39,143,251
Beginning balance at Dec. 31, 2014	941,823	58	590	1,053,601	(110,841)	(1,542)	941,866	(43)
Beginning balance (in shares) at Dec. 31, 2014		5,750,000	59,047,001
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									(4,809)	2	(4,811)	(4,809)
Common stock issuance, net (in shares)										187,055
Preferred dividends	(2,561)				(2,561)		(2,561)
Common dividends	(23,216)				(23,216)		(23,216)
Ending balance at Mar. 31, 2015	$ 932,154	$ 58	$ 592	$ 1,051,813	$ (117,168)	$ (3,087)	$ 932,208	$ (54)
Ending balance (in shares) at Mar. 31, 2015		5,750,000	59,234,056