GOODWILL AND INTANGIBLE ASSETS - NET (Goodwill Roll Forward) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Roll Forward]
Balance beginning of period	$ 115,930	$ 57,417
Effect of net foreign currency exchange rate changes	(2,373)	(2,785)
Balance end of period	109,289	115,930
North America
Goodwill [Roll Forward]
Balance beginning of period	81,464	31,078
Effect of net foreign currency exchange rate changes	(120)	(416)
Balance end of period	76,812	81,464
Europe
Goodwill [Roll Forward]
Balance beginning of period	34,466	26,339
Effect of net foreign currency exchange rate changes	(2,253)	(2,369)
Balance end of period	32,477	34,466
Russia
Goodwill [Roll Forward]
Balance beginning of period	0
Balance end of period	0	0
Other
Goodwill [Roll Forward]
Balance beginning of period	0
Balance end of period	0	0
NavigationArts
Goodwill [Roll Forward]
Acquisition		23,822
Purchase accounting adjustments	2,030	(2,058)
NavigationArts | North America
Goodwill [Roll Forward]
Acquisition		23,822
Purchase accounting adjustments	2,030	(2,058)
NavigationArts | Europe
Goodwill [Roll Forward]
Acquisition		0
Purchase accounting adjustments	0	0
AGS
Goodwill [Roll Forward]
Acquisition		33,815
Purchase accounting adjustments	(9,361)
AGS | North America
Goodwill [Roll Forward]
Acquisition		33,815
Purchase accounting adjustments	(9,361)
AGS | Europe
Goodwill [Roll Forward]
Acquisition		0
Purchase accounting adjustments	0
Netsoft
Goodwill [Roll Forward]
Purchase accounting adjustments		30
Netsoft | North America
Goodwill [Roll Forward]
Purchase accounting adjustments		30
Netsoft | Europe
Goodwill [Roll Forward]
Purchase accounting adjustments		0
Jointech
Goodwill [Roll Forward]
Purchase accounting adjustments		6,181
Jointech | North America
Goodwill [Roll Forward]
Purchase accounting adjustments		0
Jointech | Europe
Goodwill [Roll Forward]
Purchase accounting adjustments		6,181
GGA
Goodwill [Roll Forward]
Purchase accounting adjustments		(4,807)
GGA | North America
Goodwill [Roll Forward]
Purchase accounting adjustments		(4,807)
GGA | Europe
Goodwill [Roll Forward]
Purchase accounting adjustments		0
Great Fridays
Goodwill [Roll Forward]
Purchase accounting adjustments		4,315
Great Fridays | North America
Goodwill [Roll Forward]
Purchase accounting adjustments		0
Great Fridays | Europe
Goodwill [Roll Forward]
Purchase accounting adjustments		$ 4,315
Other Acquisitions [Member]
Goodwill [Roll Forward]
Acquisition	2,581
Purchase accounting adjustments	482
Other Acquisitions [Member] | North America
Goodwill [Roll Forward]
Acquisition	2,404
Purchase accounting adjustments	395
Other Acquisitions [Member] | Europe
Goodwill [Roll Forward]
Acquisition	177
Purchase accounting adjustments	$ 87