FAIR VALUE MEASUREMENTS - Changes in Level 3 liabilities measured at fair value (Details) - Level 3 - Recurring - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration, beginning of period	$ 2,173	$ 8,283
Change in fair value of contingent consideration	282	(3,682)
Contingent consideration paid	(2,553)	(2,517)
Foreign currency translation	$ 98	89
Contingent consideration, end of period		$ 2,173