Benefit Plans - Amounts Recorded in Consolidated Balance Sheets (Detail) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Non-current liabilities	$ (93.2)	$ (102.0)
Accumulated benefit obligation	112.7	119.3
Pension plans
Defined Benefit Plan Disclosure [Line Items]
Current liabilities	(5.7)	(5.6)
Non-current liabilities	(76.0)	(81.5)
Benefit obligations in excess of the fair value of plan assets	(81.7)	(87.1)
Other post-retirement plans
Defined Benefit Plan Disclosure [Line Items]
Current liabilities	(1.3)	(1.5)
Non-current liabilities	(10.0)	(12.3)
Benefit obligations in excess of the fair value of plan assets	$ (11.3)	$ (13.8)