INTANGIBLE ASSETS AND GOODWILL - Definite-lived Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount, beginning of period		$ 162,490	$ 125,190
Intangible assets acquired	$ 24,200	37,300
Accumulated amortization	(70,959)	(67,287)
Intangible assets, net	$ 115,731	95,203
Weighted average remaining years of useful life	10 years
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount, beginning of period		112,570	84,370
Intangible assets acquired	$ 19,600	28,200
Accumulated amortization	(43,943)	(41,738)
Intangible assets, net	$ 88,227	70,832
Weighted average remaining years of useful life	9 years
Trademark
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount, beginning of period		12,320	11,120
Intangible assets acquired	$ 0	1,200
Accumulated amortization	(5,402)	(5,177)
Intangible assets, net	$ 6,918	7,143
Weighted average remaining years of useful life	13 years
Developed Technology
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount, beginning of period		37,600	29,700
Intangible assets acquired	$ 3,200	7,900
Accumulated amortization	(21,614)	(20,372)
Intangible assets, net	$ 19,186	17,228
Weighted average remaining years of useful life	9 years
Non-Compete Agreements
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount, beginning of period		0	$ 0
Intangible assets acquired	$ 1,400	0
Accumulated amortization	0	0
Intangible assets, net	$ 1,400	$ 0
Weighted average remaining years of useful life	5 years