GOODWILL AND OTHER INTANGIBLE ASSETS - Carrying Amount of Goodwill (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Goodwill [Roll Forward]
Goodwill - net book value, begging of period	$ 632,469	$ 627,392	$ 632,469	$ 627,392
Acquisitions	786,904	4,492	786,904	4,492
Goodwill - net book value, end of period	$ 1,419,373	$ 631,884	$ 1,419,373	$ 631,884