UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Revenue	$ 346,293	$ 333,992
Direct costs	246,105	236,857
Gross profit	100,188	97,135
Selling, general and administrative expenses	84,592	84,678
Depreciation and amortization	2,008	2,050
Income from operations	13,588	10,407
Other expense, net	1,339	1,185
Income before income taxes	12,249	9,222
Income tax expense	3,074	3,320
Net income	9,175	5,902
Other comprehensive income (loss):
Change in fair value of interest rate swap, net of tax	517	0
Defined benefit pension plans, net of tax	0	(5)
Comprehensive income	$ 9,692	$ 5,897
Earnings per share – basic (in dollars per share)	$ 0.37	$ 0.23
Earnings per share – diluted (in dollars per share)	$ 0.37	$ 0.23
Weighted average shares outstanding – basic (in shares)	24,804	25,223
Weighted average shares outstanding – diluted (in shares)	25,094	25,509
Dividends declared per share (in dollars per share)	$ 0.12	$ 0.12