Leases - Schedule of Cash Flow Items are Included on Condensed Consolidated Statement of Cash Flows (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating cash used for operating leases	$ 12.7	$ 12.4
Operating cash used for finance leases	0.2	0.2
Financing cash used for finance leases	$ 1.5	$ 1.7