ENVIRONMENTAL REMEDIATION LIABILITIES - Schedule of Total Environmental Liabilities (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Loss Contingencies [Line Items]
Total environmental liabilities	$ 31.5	$ 33.5
Other Liabilities
Loss Contingencies [Line Items]
Total environmental liabilities	28.1	28.2
Accrued Liabilities
Loss Contingencies [Line Items]
Total environmental liabilities	$ 3.4	$ 5.3