FAIR VALUE MEASUREMENTS (Change in Fair Value at Level 3) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Change in Fair Value Measurement Categorized in Level 3 [Roll Forward]
Transfers into Level 3	$ 0	$ 0	$ 0	$ 0
Transfers out of Level 3	0	0	0	0
Contingent Consideration
Change in Fair Value Measurement Categorized in Level 3 [Roll Forward]
Balance at beginning of period	24,300,000	12,400,000	0	0
Additions	0	0	0	77,300,000
Accretion on discounted liabilities	0	500,000	0	2,000,000.0
Settlements	0	300,000	0	700,000
Unrealized (gain) loss included in earnings	(700,000)	(14,400,000)	23,600,000	(81,200,000)
Balance at end of period	$ 23,600,000	$ (1,200,000)	$ 23,600,000	$ (1,200,000)