FAIR VALUE MEASUREMENTS - Schedule of fair value hierarchy of financial instruments held (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Assets:
Financial investments	$ 0.5	$ 35.7
Deferred compensation assets	20.9
Total assets	21.4	35.7
Liabilities:
Contingent consideration liability to related party	6.3	3.9
Deferred compensation liabilities	20.9
Debt	867.1	1,215.4
Total liabilities	894.3	1,219.3
Level 1
Assets:
Financial investments	0.5	35.7
Deferred compensation assets	20.9
Total assets	21.4	35.7
Liabilities:
Deferred compensation liabilities	20.9
Total liabilities	20.9
Level 2
Liabilities:
Debt	867.1	1,215.4
Total liabilities	867.1	1,215.4
Level 3
Liabilities:
Contingent consideration liability to related party	6.3	3.9
Total liabilities	$ 6.3	$ 3.9