Selected Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income tax expense									$ (4,541)	$ 1,581	$ (2,519)
Selected Quarterly Financial Information [Abstract]
Revenues	$ 162,214	$ 140,162	$ 137,420	$ 138,757	$ 144,295	$ 164,017	$ 140,301	$ 129,623	578,553	578,236	466,498
Gross profit	27,751	10,757	15,397	12,985	11,657	24,169	16,946	14,710	66,890	67,482	40,182
Operating (loss) income	10,840	(5,354)	(2,466)	(1,482)	(5,283)	9,531	281	(455)	1,538	4,074	(7,999)
(Loss) income before income taxes	9,306	(6,703)	(3,917)	(2,827)	(6,734)	7,963	(1,310)	(1,958)	(4,141)	(2,039)	$ (10,579)
Net (loss) income	$ 9,538	$ (5,037)	$ (2,293)	$ (1,808)	$ (6,343)	$ 4,739	$ (808)	$ (1,208)	$ 400	$ (3,620)
Earnings Per Share, Basic and Diluted [Abstract]
Basic (USD per share)	$ 0.34	$ (0.18)	$ (0.08)	$ (0.07)	$ (0.23)	$ 0.17	$ (0.03)	$ (0.04)	$ 0.01	$ (0.13)	$ (0.29)
Diluted income (loss) per share (USD per share)	$ 0.34	$ (0.18)	$ (0.08)	$ (0.07)	$ (0.23)	$ 0.17	$ (0.03)	$ (0.04)	$ 0.01	$ (0.13)	$ (0.29)
Restatement Adjustment
Income tax expense	$ 800