Amount of increase (decrease) in the value of a contingent consideration liability, including, but not limited to, differences arising upon settlement.

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Amount of liability recognized arising from contingent consideration in a business combination.

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Amount of purchases, (sales), issuances and (settlements) of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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FAIR VALUE MEASUREMENTS - Additional information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Oct. 31, 2018	Jun. 11, 2018
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 22,342,000	$ 49,429,000	$ 33,464,000	$ 38,837,000
Change in fair value of contingent consideration	9,175,000	2,790,000	1,053,000	17,382,000
Contingent consideration additions	0	0	0	0
Contingent consideration payments	(3,000,000)	(2,000,000)	(6,000,000)	(6,000,000)
Ending balance	$ 28,517,000	$ 50,219,000	$ 28,517,000	$ 50,219,000
Minimum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Contingent consideration					$ 0
Maximum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Contingent consideration					$ 46,800,000	$ 4,400,000