REVENUE, DIRECT COSTS AND GROSS MARGIN Revenue, Direct Costs and Gross Margin (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenue Direct Costs And Gross Margin Line Items [Line Items]
Revenue	$ 118,108	$ 108,136	$ 335,104	$ 322,430
Direct costs	70,863	64,594	197,101	190,787
Gross margin	47,245	43,542	138,003	131,643
Contracting
Revenue Direct Costs And Gross Margin Line Items [Line Items]
Revenue	77,097	70,440	213,813	208,330
Direct costs	68,260	61,619	188,778	181,797
Gross margin	8,837	8,821	25,035	26,533
Permanent Recruitment
Revenue Direct Costs And Gross Margin Line Items [Line Items]
Revenue	31,783	28,437	91,991	84,499
Direct costs	535	627	1,751	1,812
Gross margin	31,248	27,810	90,240	82,687
Talent Management
Revenue Direct Costs And Gross Margin Line Items [Line Items]
Revenue	8,680	8,540	27,656	27,989
Direct costs	1,500	1,756	4,915	5,555
Gross margin	7,180	6,784	22,741	22,434
Other Than Temporary Contracting Permanent Recruitment and Talent Management [Domain]
Revenue Direct Costs And Gross Margin Line Items [Line Items]
Revenue	548	719	1,644	1,612
Direct costs	568	592	1,657	1,623
Gross margin	$ (20)	$ 127	$ (13)	$ (11)