Retirement Plans - Amounts Recognized in Other Comprehensive Income (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($)
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Amortization of Net actuarial loss (gain)	$ 11.5
Amortization of Net prior service credit	0.1
Amounts arising during the period, Net actuarial loss	38.5
Amounts arising during the period, Net prior service cost	(2.6)
Amounts arising during the period, Settlements	0.4
Amounts arising during the period, Foreign currency loss	(0.3)
Total	47.6
OPEB
Defined Benefit Plan Disclosure [Line Items]
Amortization of Net actuarial loss (gain)	(0.7)
Amortization of Net prior service credit	(5.5)
Amounts arising during the period, Net actuarial loss	81.7
Amounts arising during the period, Net prior service cost	0.0
Amounts arising during the period, Settlements	0.0
Amounts arising during the period, Foreign currency loss	(0.1)
Total	$ 75.4