Schedule II - Valuation and Qualifying Accounts (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Valuation Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	$ 2.0	$ 1.8	$ 5.2
Additions Acquisition Beginning Balance			0.2
Additions Charged to Costs and Expenses	1.3	0.1	(0.7)
Deductions & Write-offs	0.3	0.1	(2.9)
Balance at End of Year	3.6	2.0	1.8
Valuation Allowance for Sales Returns [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	1.8	1.4	1.0
Additions Charged to Costs and Expenses	(0.1)	0.3	0.2
Deductions & Write-offs	(0.1)	0.1	0.2
Balance at End of Year	1.6	1.8	1.4
Valuation Allowance on Deferred Tax Asset [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	30.6	27.4	17.9
Additions Acquisition Beginning Balance			5.9
Additions Charged to Costs and Expenses	2.3	4.2	4.9
Deductions & Write-offs	(6.7)	(1.0)	(1.3)
Balance at End of Year	$ 26.2	$ 30.6	$ 27.4