GOODWILL AND OTHER INTANGIBLE ASSETS - Change in the goodwill (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Change in the goodwill
Goodwill beginning of period	$ 883,119	$ 538,113
Cumulative impairment losses beginning of period	(22,624)	(22,624)
Balance beginning of period	860,495	515,489
Goodwill acquired	128,391	347,496
Other	(180)	(2,490)
Goodwill period increase (decrease)	128,211	345,006
Goodwill end of period	1,011,330	883,119
Cumulative impairment losses end of period	(22,624)	(22,624)
Balance end of period	$ 988,706	$ 860,495