Consolidated Statements of Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Total Stockholders' Equity	Preferred Stock	Common Shares	Additional Paid-in Capital	Common Stock Dividends in excess of Earnings	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interest - Unit holders in Operating Partnership
Balance at Dec. 31, 2011	$ 309,909	$ 230,693	$ 69,000	$ 159	$ 179,919	$ (18,385)		$ 79,216
Balance (in shares) at Dec. 31, 2011				15,901,560
Increase (Decrease) in Stockholders' Equity
Proceeds from sales of common stock	237,568	237,568		176	237,392
Proceeds from sales of common stock (in shares)				17,537,500
Offering costs	(10,863)	(10,863)			(10,863)
Issuance of restricted stock, net				1	(1)
Issuance of restricted stock, net (in shares)				87,025
Issuance of common stock (in shares)				9,790
Dividends and distributions, net	(30,908)	(24,970)	(4,659)			(20,311)		(5,938)
Non-cash compensation	1,457	746			746			711
Issuance of units for acquisition fee	225							225
Conversion of operating partnership units to common stock		13,161		13	13,148			(13,161)
Conversion of operating partnership units to common stock (in shares)				1,335,224
Rebalancing of noncontrolling interest		(11,507)			(11,507)			11,507
Comprehensive income (loss)	(577)	(427)					(427)	(150)
Net income (loss)	(7,805)	(4,561)	4,659			(9,220)		(3,244)
Balance at Sep. 30, 2012	499,006	429,840	69,000	349	408,834	(47,916)	(427)	69,166
Balance (in shares) at Sep. 30, 2012				34,871,099
Balance at Dec. 31, 2012	489,460	427,605	69,000	357	419,643	(61,024)	(371)	61,855
Balance (in shares) at Dec. 31, 2012				35,698,582
Increase (Decrease) in Stockholders' Equity
Proceeds from sales of common stock	154,669	154,669		82	154,587
Proceeds from sales of common stock (in shares)				8,247,322
Issuance of series B preferred stock	70,000	70,000	70,000
Offering costs	(8,457)	(8,457)			(8,457)
Issuance of restricted stock, net				1	(1)
Issuance of restricted stock, net (in shares)				96,287
Issuance of common stock (in shares)				7,871
Dividends and distributions, net	(51,657)	(45,323)	(6,783)			(38,540)		(6,334)
Non-cash compensation	2,227	1,020			1,020			1,207
Issuance of units	11,499							11,499
Conversion of operating partnership units to common stock		23			23			(23)
Conversion of operating partnership units to common stock (in shares)				2,186
Rebalancing of noncontrolling interest		(4,304)			(4,304)			4,304
Comprehensive income (loss)	2,632	2,277					2,277	355
Net income (loss)	(308)	650	6,783			(6,133)		(958)
Balance at Sep. 30, 2013	$ 670,065	$ 598,160	$ 139,000	$ 440	$ 562,511	$ (105,697)	$ 1,906	$ 71,905
Balance (in shares) at Sep. 30, 2013				44,052,248