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, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Leases [Abstract]
Operating cash used for operating leases	$ (3.0)	$ (3.2)	$ (6.0)	$ (6.5)
Operating cash used for finance leases	(0.1)	(0.1)	(0.1)	(0.1)
Financing cash used for finance leases	$ (0.4)	$ (0.3)	$ (0.8)	$ (0.7)