FAIR VALUE MEASUREMENTS - Additional information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 9,046,000	$ 22,342,000	$ 8,249,000	$ 33,464,000
Change in fair value of contingent consideration	(8,850,000)	9,175,000	(8,053,000)	1,053,000
Contingent consideration additions	0	0	0	0
Contingent consideration payments	0	(3,000,000)	0	(6,000,000)
Ending balance	196,000	$ 28,517,000	196,000	$ 28,517,000
Minimum
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Contingent consideration	0		0
Maximum
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Contingent consideration	$ 23,400,000		$ 23,400,000