Income Taxes - Roll-forward of Unrecognized Tax Benefits and Associated Accrued Interest and Penalties (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Income Tax Contingency [Line Items]
Opening balance at January 1	$ 13.4
Net change for tax positions of prior periods	0.3
Closing balance at March 31	13.7
Current	0.0
Non-current	13.7	$ 13.4
Interest and Penalties [Member]
Income Tax Contingency [Line Items]
Opening balance at January 1	3.2
Net change for tax positions of prior periods	0.2
Closing balance at March 31	3.4
Current	0.0
Non-current	3.4
Unrecognized Tax Benefits [Member]
Income Tax Contingency [Line Items]
Opening balance at January 1	10.2
Net change for tax positions of prior periods	0.1
Closing balance at March 31	10.3
Current	0.0
Non-current	$ 10.3