INTANGIBLE ASSETS - Summary of Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 214,030	$ 214,095
Accumulated Amortization	(127,458)	(124,197)
Net Carrying Amount	86,572	89,898
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	175,130	175,156
Accumulated Amortization	(91,862)	(88,783)
Net Carrying Amount	83,268	86,373
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	5,509	5,503
Accumulated Amortization	(5,509)	(5,503)
Net Carrying Amount	0	0
Trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	24,710	24,743
Accumulated Amortization	(22,367)	(22,252)
Net Carrying Amount	2,343	2,491
Technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	7,834	7,843
Accumulated Amortization	(6,933)	(6,885)
Net Carrying Amount	901	958
Licenses
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	847	850
Accumulated Amortization	(787)	(774)
Net Carrying Amount	$ 60	$ 76