Pension and Other Employee Benefits - Other Recognized Change in Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Retirement Benefits [Abstract]
Incurred net actuarial (loss) gain	$ 7.9	$ 1.3	$ (2.6)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Immediate Recognition of Actuarial Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, after Tax	Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, after Tax	Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, after Tax
Amortization of prior service credit	$ (0.1)		$ (0.1)
Amortization of net actuarial (loss) gain	0.1	$ 0.6	0.5
Settlement recognition of net actuarial (loss)		0.7
Total recognized in accumulated other comprehensive (loss) income (net of $(2.2 million), ($0.6 million) and $0.5 million) of tax (loss)/benefit, respectively)	$ 7.9	$ 2.6	$ (2.2)