Consolidated Statements of Changes in Equity (USD $) In Thousands, except Share data, unless otherwise specified	Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit and Distributions	Total Shareholders' Equity	Noncontrolling Interest Operating partnership	Noncontrolling Interest Joint venture	Total
Balance at beginning of year at Dec. 31, 2011	$ 20	$ 273	$ 288,902		$ (11,020)	$ 278,175	$ 41,274		$ 319,449
Balance (in shares) at Dec. 31, 2011	2,000,000	27,278,000
Changes in equity
Net proceeds from sale of common stock		138	106,267			106,405			106,405
Net proceeds from sale of common stock (in shares)		13,800,000
Net proceeds from sale of preferred stock	30		72,423			72,453			72,453
Net proceeds from sale of preferred stock (in shares)	3,000,000
Common stock redemption of common units		49	205			254	(254)
Common stock redemption of common units (in shares)		4,873,625
Dividends paid					(19,889)	(19,889)	(3,177)		(23,066)
Equity-based compensation		2	1,023			1,025	180		1,205
Equity-based compensation (in shares)		208,027
Other comprehensive income (loss)				(528)		(528)	(111)		(639)
Net income (loss)					(1,076)	(1,076)	(1,194)		(2,270)
Balance at end of year at Dec. 31, 2012	50	462	468,820	(528)	(31,985)	436,819	36,718		473,537
Balance (in shares) at Dec. 31, 2012	5,000,000	46,159,652
Changes in equity
Net proceeds from sale of common stock		345	299,727			300,072			300,072
Net proceeds from sale of common stock (in shares)		34,500,000
Net proceeds from sale of preferred stock	34		81,689			81,723			81,723
Net proceeds from sale of preferred stock (in shares)	3,400,000
Common stock redemption of common units		44	30,574			30,618	(30,618)
Common stock redemption of common units (in shares)		4,414,950
Contribution by noncontrolling interests in joint venture								7,500	7,500
Dividends paid					(46,470)	(46,470)	(1,124)		(47,594)
Equity-based compensation		3	2,048			2,051	73		2,124
Equity-based compensation (in shares)		327,806
Other comprehensive income (loss)				(851)		(851)	(30)		(881)
Net income (loss)					5,878	5,878	(297)	316	5,897
Balance at end of year at Dec. 31, 2013	84	854	882,858	(1,379)	(72,577)	809,840	4,722	7,816	822,378
Balance (in shares) at Dec. 31, 2013	8,400,000	85,402,408
Changes in equity
Common stock redemption of common units		4	2,425			2,429	(2,429)
Common stock redemption of common units (in shares)		438,631
Common units issued for acquisition							3,685		3,685
Acquisition of non-controlling interest in joint venture			(415)			(415)		(7,817)	(8,232)
Dividends paid					(56,073)	(56,073)	(477)		(56,550)
Equity-based compensation		(3)	(3,479)			(3,482)	(42)		(3,524)
Equity-based compensation (in shares)		321,269
Other			(156)			(156)			(156)
Other (in shares)		(12,588)
Other comprehensive income (loss)				(367)		(367)	(4)		(371)
Net income (loss)					20,871	20,871	51	1	20,923
Balance at end of year at Dec. 31, 2014	$ 84	$ 861	$ 888,191	$ (1,746)	$ (107,779)	$ 779,611	$ 5,590		$ 785,201
Balance (in shares) at Dec. 31, 2014	8,400,000	86,149,720