Leases - Components of Lease Expense (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Lease Cost
Operating lease cost	$ 2.4	$ 1.4	$ 4.9	$ 2.6
Financing lease cost:
Depreciation of lease assets	0.4	0.3	0.7	0.7
Interest on lease liabilities	0.1	0.1	0.2	0.1
Sublease income	(0.1)	(0.7)	(0.2)	(1.3)
Total lease cost, net	$ 2.8	$ 1.1	$ 5.6	$ 2.1