Quarterly Financial Information (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended									12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Effect of Fourth Quarter Events [Line Items]
Total revenues	$ 34,984		$ 37,811	$ 36,526	$ 32,998	$ 32,338	$ 32,146	$ 33,186	$ 30,716	$ 142,319	$ 128,386	$ 86,194
Operating income	(1,585)		6,856	5,884	4,292	5,307	5,014	2,968	2,601	15,447	15,890	7,181
Net income (Loss)	(9,342)		4,853	3,940	2,167	2,268	9,050	460	(980)	1,618	10,798	3,781
Net income (loss) attributable to common stockholders	$ (11,985)	[1]	$ 3,677	$ 2,771	$ 1,006	$ 1,110	$ 7,839	$ (676)	$ (1,635)	$ (4,531)	$ 6,638	$ 3,730
Net income (loss) attributable to common stockholders - basic and diluted	$ (0.18)		$ 0.06	$ 0.04	$ 0.02	$ 0.03	$ 0.20	$ (0.02)	$ (0.05)	$ (0.08)	$ 0.19	$ 0.12

[1] The purchase price allocation for our Copper Beech acquisition was finalized and all required adjustments are reflected in our fourth quarter information.