Pension and Other Employee Benefits - Amounts Recognized in Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Retirement Benefits [Abstract]
Unrecognized actuarial (loss) gain	$ 6.0	$ (2.1)	$ (4.2)
Unrecognized prior service credit	0.8	1.0	0.5
Accumulated other comprehensive (loss) income (net of ($1.4 million), $0.8 million and $1.0 million of tax (loss)/benefit, respectively)	$ 6.8	$ (1.1)	$ (3.7)