Revenue from Contracts with Customers - Schedule of Deferred Revenue and Customer Advances by Arrangement (Parenthetical) (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
Change in Contract with Customer, Liability [Line Items]
Long-term deferred revenue	$ 5.6	$ 3.3
Deferred revenue and customer advances	31.2		$ 21.5
Deferred Revenue [Member]
Change in Contract with Customer, Liability [Line Items]
Deferred revenue and customer advances	18.3	12.4
Customer Advances [Member]
Change in Contract with Customer, Liability [Line Items]
Deferred revenue and customer advances	$ 12.8	$ 9.1