ACQUISITIONS - Acquired Intangibles (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
2021 Acquisitions
Acquired finite-lived intangible assets
Estimated Fair Value of Asset	$ 63,808
2021 Acquisitions | Acquired technology
Acquired finite-lived intangible assets
Weighted average useful life (in years)	10 years
Estimated Fair Value of Asset	$ 32,145
2021 Acquisitions | Customer relationships
Acquired finite-lived intangible assets
Weighted average useful life (in years)	11 years 6 months
Estimated Fair Value of Asset	$ 30,258
2021 Acquisitions | Trademarks and trade names
Acquired finite-lived intangible assets
Weighted average useful life (in years)	0 years
Estimated Fair Value of Asset	$ 0
2021 Acquisitions | License agreements and other
Acquired finite-lived intangible assets
Weighted average useful life (in years)	3 months
Estimated Fair Value of Asset	$ 1,405
2020 Acquisitions
Acquired finite-lived intangible assets
Estimated Fair Value of Asset		$ 79,900
2020 Acquisitions | Acquired technology
Acquired finite-lived intangible assets
Weighted average useful life (in years)		4 years
Estimated Fair Value of Asset		$ 4,600
2020 Acquisitions | Customer relationships
Acquired finite-lived intangible assets
Weighted average useful life (in years)		13 years
Estimated Fair Value of Asset		$ 62,300
2020 Acquisitions | Trademarks and trade names
Acquired finite-lived intangible assets
Weighted average useful life (in years)		4 years
Estimated Fair Value of Asset		$ 10,300
2020 Acquisitions | License agreements and other
Acquired finite-lived intangible assets
Weighted average useful life (in years)		3 months
Estimated Fair Value of Asset		$ 2,700