Retirement Plans - Components of Estimated Net Periodic Benefit Income (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 1.8	$ 1.6
Expected return on assets	(2.8)	(3.5)
Amortization, net	0.8	0.9
Net pension plan income	$ (0.2)	$ (1.0)