REVENUE, DIRECT COSTS AND GROSS MARGIN (Details) - USD ($) $ 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
Revenue Direct Costs And Gross Margin Line Items [Line Items]
Revenue	$ 121,617	$ 118,108	$ 113,591	$ 103,405	$ 100,314	$ 108,136	$ 113,067	$ 101,227	$ 456,721	$ 422,744	$ 463,197
Direct costs									269,985	248,327	275,487
Gross margin	$ 48,733	$ 47,245	$ 48,326	$ 42,432	$ 42,774	$ 43,542	$ 46,839	$ 41,262	186,736	174,417	187,710
Temporary Contracting
Revenue Direct Costs And Gross Margin Line Items [Line Items]
Revenue									292,102	270,777	305,052
Direct costs									258,243	236,654	262,322
Gross margin									33,859	34,123	42,730
Permanent Recruitment
Revenue Direct Costs And Gross Margin Line Items [Line Items]
Revenue									124,367	112,582	118,934
Direct costs									2,769	2,429	2,733
Gross margin									121,598	110,153	116,201
Talent Management [Member]
Revenue Direct Costs And Gross Margin Line Items [Line Items]
Revenue									38,092	37,204	37,425
Direct costs									6,687	7,216	8,681
Gross margin									31,405	29,988	28,744
Other Than Temporary Contracting, Permanent Recruitment and Talent Management [Member] [Member]
Revenue Direct Costs And Gross Margin Line Items [Line Items]
Revenue									2,160	2,181	1,786
Direct costs									2,286	2,028	1,751
Gross margin									$ (126)	$ 153	$ 35