GOODWILL AND INTANGIBLE ASSETS - Intangible Assets by Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Intangible Assets [Roll Forward]
Balance, beginning of period	$ 263,467	$ 164,539
Acquisitions	154,602	116,740
Amortization	(34,213)	(19,374)	$ (13,368)
Adjustment to prior year preliminary purchase price allocation	(874)	1,562
Balance, end of period	382,982	263,467	164,539
Manufacturing [Member]
Intangible Assets [Roll Forward]
Balance, beginning of period	220,540	149,853
Acquisitions	112,517	85,350
Amortization	(27,413)	(16,225)	(10,600)
Adjustment to prior year preliminary purchase price allocation	(1,159)	1,562
Balance, end of period	304,485	220,540	149,853
Distribution [Member]
Intangible Assets [Roll Forward]
Balance, beginning of period	42,927	14,686
Acquisitions	42,085	31,390
Amortization	(6,800)	(3,149)	(2,700)
Adjustment to prior year preliminary purchase price allocation	285	0
Balance, end of period	$ 78,497	$ 42,927	$ 14,686