ACQUISITIONS (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Mar. 31, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Business Acquisition [Line Items]
Payments for acquisitions, net of cash acquired				$ 0	$ 27,001
Net assets acquired based on fair values:
Goodwill	$ 239,185			239,185		$ 239,256
Net income	5,678	$ 7,208		10,770	11,603
Amortization of intangible assets	$ 3,756	$ 4,443		$ 7,499	$ 8,754
Basic earnings per share (in dollars per share)	$ 0.11	$ 0.14		$ 0.21	$ 0.22
OilCareers [Member]
Business Acquisition [Line Items]
Cash consideration paid		$ 300	$ 26,100
Net assets acquired based on fair values:
Business Combination, Acquired Receivables, Fair Value		1,082			$ 1,082
Acquired intangible assets		14,508			14,508
Goodwill		15,078			15,078
Fixed Assets		98			98
Other Assets		196			196
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets		30,962			30,962
Accounts payable and accrued expenses		567			567
Deferred Revenue		1,081			1,081
Deferred Income Taxes and Other Tax Liabilities, Noncurrent		2,916			2,916
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		4,564			4,564
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net		26,398			26,398
Business Acquisition, Goodwill, Expected Tax Deductible Amount		1,200			1,200
Business Combination, Acquired Receivables, Fair Value		$ 1,082			$ 1,082
Technology Equipment [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				3 years 9 months		3 years 6 months
Technology Equipment [Member] | OilCareers [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				9 months 18 days
Trademarks, Other [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				6 years 1 month		6 years 1 month
Trademarks, Other [Member] | OilCareers [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				2 years
Customer Lists [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				5 years 2 months		5 years 6 months
Customer Lists [Member] | OilCareers [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				7 years
Candidate Database [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				2 years 9 months		2 years 8 months
Candidate Database [Member] | OilCareers [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				2 years