FINANCIAL INSTRUMENTS - Unobservable Inputs of Fair Value Measurements (Details) - Contingent Consideration Arrangements - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Contingent Consideration Arrangement [Roll Forward]
Balance at January 1	$ (2,647)	$ (33,871)
Fair value adjustments	(1,456)	(5,801)
Included in other comprehensive income (loss)	45	(1,404)
Fair value at date of acquisition	(25,521)	0
Settlements	948	38,429
Balance at December 31	$ (28,631)	$ (2,647)