FAIR VALUE MEASUREMENT - Fair value hierarchy of financial instruments held (Details) - USD ($) $ in Millions	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021
Assets:
Deferred compensation plan assets	$ 25.4		$ 28.0
Digital assets - safeguarded assets	24.0	$ 22.4
Digital assets held	0.9
Total assets	52.3		37.1
Liabilities:
Contingent consideration liabilities	47.5		70.5
Deferred compensation plan liabilities	25.4		28.0
Digital assets - safeguarded liabilities	24.0	$ 22.4
Debt	1,859.8		1,299.3
Total liabilities	1,956.7		1,397.8
Level 1
Assets:
Deferred compensation plan assets	25.4		28.0
Digital assets - safeguarded assets	24.0
Digital assets held	0.9
Total assets	52.3		37.1
Liabilities:
Deferred compensation plan liabilities	25.4		28.0
Digital assets - safeguarded liabilities	24.0
Total liabilities	49.4		28.0
Level 2
Liabilities:
Debt	1,859.8		1,299.3
Total liabilities	1,859.8		1,299.3
Level 3
Liabilities:
Contingent consideration liabilities	47.5		70.5
Total liabilities	47.5		70.5
U.S. Treasury securities
Assets:
Investments fair value	0.5		9.1
U.S. Treasury securities | Level 1
Assets:
Investments fair value	0.5		$ 9.1
Canadian short-term investments
Assets:
Investments fair value	1.5
Canadian short-term investments | Level 1
Assets:
Investments fair value	$ 1.5