GOODWILL AND OTHER INTANGIBLE ASSETS - Amortization of the Acquired Intangible Assets Other than Goodwill (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Amortized intangible assets
Gross Carrying Amount	$ 154,759	$ 154,776
Accumulated Amortization	(67,837)	(59,655)
Customer Relationships
Amortized intangible assets
Gross Carrying Amount	143,650	143,479
Accumulated Amortization	$ (58,187)	(50,076)
Customer Relationships | Minimum
Finite-Lived Intangible Assets [Line Items]
Amortization Period	10 years
Customer Relationships | Maximum
Finite-Lived Intangible Assets [Line Items]
Amortization Period	14 years
Patents
Finite-Lived Intangible Assets [Line Items]
Amortization Period	28 years
Amortized intangible assets
Gross Carrying Amount	$ 650	650
Accumulated Amortization	$ (623)	(616)
Technology
Finite-Lived Intangible Assets [Line Items]
Amortization Period	15 years
Amortized intangible assets
Gross Carrying Amount	$ 2,500	2,500
Accumulated Amortization	(1,227)	(1,144)
Trade Names
Amortized intangible assets
Gross Carrying Amount	7,495	7,495
Accumulated Amortization	$ (7,336)	(7,167)
Trade Names | Maximum
Finite-Lived Intangible Assets [Line Items]
Amortization Period	5 years
License Agreements
Finite-Lived Intangible Assets [Line Items]
Amortization Period	10 years
Amortized intangible assets
Gross Carrying Amount	$ 0	185
Accumulated Amortization	0	(185)
Other
Amortized intangible assets
Gross Carrying Amount	464	467
Accumulated Amortization	$ (464)	$ (467)
Other | Minimum
Finite-Lived Intangible Assets [Line Items]
Amortization Period	7 years
Other | Maximum
Finite-Lived Intangible Assets [Line Items]
Amortization Period	15 years