CONSOLIDATED STATEMENTS OF OPERATIONSAND COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Net service revenues	$ 1,319,706	$ 1,319,238	$ 1,217,331
Direct costs of services	911,207	905,124	842,750
Gross profit	408,499	414,114	374,581
Selling, general and administrative expenses	341,196	330,416	315,338
Depreciation and amortization	8,701	9,831	9,894
Income from operations	58,602	73,867	49,349
Other expense, net	2,647	2,195	1,392
Income from continuing operations, before income taxes	55,955	71,672	47,957
Income tax expense	23,182	28,848	18,559
Income from continuing operations	32,773	42,824	29,398
Income from discontinued operations, net of income taxes	0	0	61,517
Net income	32,773	42,824	90,915
Other comprehensive (loss) income:
Defined benefit pension and post-retirement plans, net of tax	(134)	689	(688)
Comprehensive income	$ 32,639	$ 43,513	$ 90,227
Earnings per share – basic:
From continuing operations (in dollars per share)	$ 1.26	$ 1.53	$ 0.94
From discontinued operations (in dollars per share)	0.00	0.00	1.95
Earnings per share – basic (in dollars per share)	1.26	1.53	2.89
Earnings per share – diluted:
From continuing operations (in dollars per share)	1.25	1.52	0.93
From discontinued operations (in dollars per share)	0.00	0.00	1.94
Earnings per share – diluted (in dollars per share)	$ 1.25	$ 1.52	$ 2.87
Weighted average shares outstanding - basic (in shares)	26,099	27,910	31,475
Weighted average shares outstanding – diluted (in shares)	26,274	28,190	31,691
Cash dividends declared per share (in dollars per share)	$ 0.48	$ 0.45	$ 0.41