GOODWILL AND OTHER INTANGIBLE ASSETS - Summary of Components of Amortizing Intangible Assets, Including Capitalized Software (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 123,941	$ 121,893
Accumulated Amortization	(98,275)	(93,915)
Acquired and developed technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	52,825	52,195
Accumulated Amortization	(48,063)	(45,995)
Customer relationships and trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	71,116	69,698
Accumulated Amortization	$ (50,212)	$ (47,920)