FAIR VALUE MEASUREMENTS - Additional information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 8,249,000	$ 33,464,000
Change in fair value of contingent consideration	797,000	(8,122,000)
Contingent consideration additions	0	0
Contingent consideration payments	0	(3,000,000)
Ending balance	9,046,000	$ 22,342,000
Minimum
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Contingent consideration	0
Maximum
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Contingent consideration	$ 23,400,000