Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Revenue	$ 509,208	$ 490,559	$ 490,280
Cost of revenue	427,181	410,402	408,288
Gross profit	82,027	80,157	81,992
Selling, general and administrative expenses	57,419	48,597	47,748
Restructuring charges	3,317	0	1,551
Gain (loss) on change in fair value of contingent consideration, net	1,620	(136)	(371)
Operating income	22,911	31,424	32,322
Interest expense	3,132	1,568	1,381
Other (expense) income (including interest income of $43 in 2017, $94 in 2016 and $149 in 2015)	(90)	178	(1,318)
Income before income taxes	19,689	30,034	29,623
Income tax expense	6,798	9,787	10,834
Net income	$ 12,891	$ 20,247	$ 18,789
Basic weighted average shares outstanding (in shares)	16,748	16,696	17,110
Diluted weighted average shares outstanding (in shares)	16,873	16,791	17,264
Per common share data:
Basic earnings per share (in dollars per share)	$ 0.77	$ 1.21	$ 1.10
Diluted earnings per share (in dollars per share)	$ 0.76	$ 1.21	$ 1.09