GOODWILL AND OTHER INTANGIBLE ASSETS - Carrying Amount of Goodwill (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019
Goodwill [Roll Forward]
Goodwill - net book value, begging of period	$ 1,428,610	$ 1,427,883	$ 1,425,542	$ 632,469	$ 632,469	$ 632,469
Purchase accounting adjustments and acquisitions	0	727	2,341	786,904	0	0
Goodwill - net book value, end of period	$ 1,428,610	$ 1,428,610	$ 1,427,883	$ 1,419,373	$ 632,469	$ 632,469