GOODWILL - Roll Forward (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2016 USD ($)
Goodwill [Roll Forward]
Balance as of January 1, 2016	$ 115,930
Effect of net foreign currency exchange rate changes	795
Balance as of March 31, 2016	118,615
North America
Goodwill [Roll Forward]
Balance as of January 1, 2016	81,464
Effect of net foreign currency exchange rate changes	139
Balance as of March 31, 2016	83,493
Europe
Goodwill [Roll Forward]
Balance as of January 1, 2016	34,466
Effect of net foreign currency exchange rate changes	656
Balance as of March 31, 2016	35,122
NavigationArts
Goodwill [Roll Forward]
Purchase accounting adjustments	2,030
NavigationArts | North America
Goodwill [Roll Forward]
Purchase accounting adjustments	2,030
NavigationArts | Europe
Goodwill [Roll Forward]
Purchase accounting adjustments	0
AGS
Goodwill [Roll Forward]
Purchase accounting adjustments	(140)
AGS | North America
Goodwill [Roll Forward]
Purchase accounting adjustments	(140)
AGS | Europe
Goodwill [Roll Forward]
Purchase accounting adjustments	$ 0