GOODWILL AND OTHER INTANGIBLE ASSETS - Changes in Carrying Amount of Goodwill and Other Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill
Balance at beginning of period	$ 194,052	$ 187,591
Translation adjustment	0	0
Balance at end of period	194,052	194,052	$ 187,591
Other Intangible Assets
Balance at beginning of period	67,207	78,525
Translation adjustment	449	(917)
Amortization	(15,074)	(16,586)	(17,266)
Balance at end of period	52,582	67,207	78,525
Total
Balance at beginning of period	261,259	266,116
Translation adjustment	449	(917)
Acquisition of ASI		12,646
Amortization	(15,074)	(16,586)	(17,266)
Balance at end of period	$ 246,634	261,259	$ 266,116
ASI
Goodwill
Acquisition of ASI		6,461
Other Intangible Assets
Acquisition of ASI		$ 6,185