GOODWILL AND OTHER INTANGIBLE ASSETS - Change in goodwill (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Change in the goodwill
Goodwill beginning of period	$ 1,112,855	$ 883,119
Cumulative impairment losses beginning of period	(22,624)	(22,624)
Balance beginning of period	1,090,231	860,495
Goodwill acquired	26,545	229,799
Other	(4,996)	(63)
Goodwill period increase (decrease)	21,549	229,736
Goodwill end of period	1,134,404	1,112,855
Cumulative impairment losses end of period	(22,624)	(22,624)
Balance end of period	$ 1,111,780	$ 1,090,231