GOODWILL AND OTHER INTANGIBLE ASSETS - Intangible Assets (Detail) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Intangible Assets By Major Class [Line Items]
Accumulated Amortization	$ 669.3	$ 641.6
Gross Carrying Amount	1,723.3	1,729.0
Net Value	1,054.0	1,087.4
Operating permits
Intangible Assets By Major Class [Line Items]
Carrying amount, indefinite lived intangible assets	77.8	79.6
Tradenames
Intangible Assets By Major Class [Line Items]
Carrying amount, indefinite lived intangible assets	315.6	315.3
Customer relationships
Intangible Assets By Major Class [Line Items]
Gross Carrying Amount	1,310.7	1,314.9
Accumulated Amortization	657.1	630.2
Net Value	653.6	684.7
Covenants not-to-compete
Intangible Assets By Major Class [Line Items]
Gross Carrying Amount	3.5	3.5
Accumulated Amortization	3.1	3.0
Net Value	0.4	0.5
Tradenames
Intangible Assets By Major Class [Line Items]
Gross Carrying Amount	3.6	3.6
Accumulated Amortization	1.3	1.3
Net Value	2.3	2.3
Operating permits
Intangible Assets By Major Class [Line Items]
Gross Carrying Amount	11.5	11.5
Accumulated Amortization	7.2	6.5
Net Value	4.3	5.0
Other
Intangible Assets By Major Class [Line Items]
Gross Carrying Amount	0.6	0.6
Accumulated Amortization	0.6	0.6
Net Value	$ 0.0	$ 0.0