Selected Quarterly Financial Data (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Selected Quarterly Financial Information [Abstract]
Revenues	$ 107,333	$ 106,976	$ 90,251	$ 81,258	$ 106,412	$ 88,992	$ 84,081	$ 75,059	$ 385,818	$ 354,544	$ 292,042
Gross profit	18,168	12,906	5,873	7,647	12,806	5,585	7,786	5,827	44,594	32,004	14,370
Operating (loss) income	7,429	5,047	(2,256)	(317)	3,916	(2,389)	231	(1,864)	9,903	(106)	(14,203)
(Loss) income before income taxes	7,457	4,838	(1,899)	(344)	3,416	(2,475)	190	(1,737)	10,052	(606)	(16,506)
Net (loss) income	5,288	2,962	(1,163)	(210)	2,190	(974)	212	(1,097)	6,877	331
Net income (loss) attributable to noncontrolling interest					56	(31)	(18)	(7)	0	0	0
Net (loss) income attributable to common stockholders	$ 5,288	$ 2,962	$ (1,163)	$ (210)	$ 2,134	$ (943)	$ 230	$ (1,090)	$ 6,877	$ 331	$ (11,866)
Earnings Per Share, Basic and Diluted [Abstract]
Basic (in dollars per share)	$ 0.19	$ 0.11	$ (0.04)	$ (0.01)	$ 0.08	$ (0.03)	$ 0.01	$ (0.04)	$ 0.25	$ 0.01	$ (0.44)
Diluted loss per share (in dollars per share)	$ 0.19	$ 0.11	$ (0.04)	$ (0.01)	$ 0.08	$ (0.03)	$ 0.01	$ (0.04)	$ 0.25	$ 0.01	$ (0.44)