ACQUISITIONS - Estimated Fair Values (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015	Nov. 16, 2015	Jul. 10, 2015
Business Acquisition [Line Items]
Goodwill	$ 110,668	$ 115,930
NavigationArts
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments [Abstract]
Adjustment to net assets acquired	(1,797)
NavigationArts | As Originally Reported
Business Acquisition [Line Items]
Cash and cash equivalents				$ 1,317
Trade receivables and other current assets				3,920
Property and equipment and other long-term assets				230
Deferred tax asset				0
Acquired intangible assets				1,500
Goodwill				23,822
Total assets acquired				30,789
Accounts payable and accrued expenses				871
Bank loans and other long-term liabilities				0
Deferred revenue				50
Due to employees				596
Deferred tax liability				525
Total liabilities assumed				2,042
Net assets acquired				$ 28,747
NavigationArts | Current
Business Acquisition [Line Items]
Cash and cash equivalents	1,317
Trade receivables and other current assets	3,920
Property and equipment and other long-term assets	230
Deferred tax asset	0
Acquired intangible assets	2,800
Goodwill	23,794
Total assets acquired	32,061
Accounts payable and accrued expenses	871
Bank loans and other long-term liabilities	0
Deferred revenue	50
Due to employees	596
Deferred tax liability	0
Total liabilities assumed	1,517
Net assets acquired	30,544
AGS
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments [Abstract]
Adjustment to net assets acquired	140
AGS | As Originally Reported
Business Acquisition [Line Items]
Cash and cash equivalents			$ 1,727
Trade receivables and other current assets			10,600
Property and equipment and other long-term assets			1,665
Deferred tax asset			4,996
Acquired intangible assets			10,000
Goodwill			33,815
Total assets acquired			62,803
Accounts payable and accrued expenses			3,087
Bank loans and other long-term liabilities			0
Deferred revenue			1,049
Due to employees			3,010
Deferred tax liability			3,800
Total liabilities assumed			10,946
Net assets acquired			$ 51,857
AGS | Current
Business Acquisition [Line Items]
Cash and cash equivalents	1,727
Trade receivables and other current assets	10,600
Property and equipment and other long-term assets	1,665
Deferred tax asset	4,996
Acquired intangible assets	22,700
Goodwill	25,801
Total assets acquired	67,489
Accounts payable and accrued expenses	2,792
Bank loans and other long-term liabilities	295
Deferred revenue	1,049
Due to employees	3,010
Deferred tax liability	8,626
Total liabilities assumed	15,772
Net assets acquired	51,717
Total | As Originally Reported
Business Acquisition [Line Items]
Cash and cash equivalents	3,044
Trade receivables and other current assets	14,520
Property and equipment and other long-term assets	1,895
Deferred tax asset	4,996
Acquired intangible assets	11,500
Goodwill	57,637
Total assets acquired	93,592
Accounts payable and accrued expenses	3,958
Bank loans and other long-term liabilities	0
Deferred revenue	1,099
Due to employees	3,606
Deferred tax liability	4,325
Total liabilities assumed	12,988
Net assets acquired	80,604
Total | Current
Business Acquisition [Line Items]
Cash and cash equivalents	3,044
Trade receivables and other current assets	14,520
Property and equipment and other long-term assets	1,895
Deferred tax asset	4,996
Acquired intangible assets	25,500
Goodwill	49,595
Total assets acquired	99,550
Accounts payable and accrued expenses	3,663
Bank loans and other long-term liabilities	295
Deferred revenue	1,099
Due to employees	3,606
Deferred tax liability	8,626
Total liabilities assumed	17,289
Net assets acquired	$ 82,261