Supplemental Cash Flow Information - Schedule Of Noncash Investing and Financing Activities (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Supplemental Cash Flow Elements [Abstract]
Accrued liabilities for purchases of property, plant and equipment	$ 22.0	$ 18.7
Acquisition of assets through swap		1.1
Receivable issued in connection with sale of property, plant and equipment		$ 0.3
Right-of-use assets obtained in exchange for new operating lease liabilities	18.0
Remeasurement of operating leases	1.1
Right-of-use assets obtained in exchange for new finance lease liabilities	$ 1.1