Leases - Schedule of Cash Flow Items are Included on Condensed Consolidated Statement of Cash Flows (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Leases [Abstract]
Operating cash used for operating leases	$ 3.2	$ 3.0	$ 6.5	$ 6.1
Operating cash used for finance leases	0.1	0.1	0.1	0.1
Financing cash used for finance leases	$ 0.3	$ 0.4	$ 0.7	$ 0.9