Pension and Other Employee Benefits - Reconciliation of Benefit Obligation, Fair Value of Plan Assets and Funded Status of Respective Defined Benefit (Pension) and Postretirement Benefit Plans (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Amounts recognized in the balance sheet consist of:
Total non-current liabilities	$ 17.3	$ 29.9
Pension Benefits [Member]
Change in benefit obligation:
Obligation at beginning of year	43.2	48.3	$ 42.2
Service cost	0.6	0.7	0.7
Interest cost	0.3	0.2	0.3
Contributions	0.2	0.2	0.2
Actuarial (gains) losses	(9.6)	(0.6)	2.4
Amendments		(0.7)	0.9
Foreign exchange effect	(1.7)	(2.7)	4.0
Benefits paid	(2.0)	(2.2)	(2.4)
Obligation at end of year	31.0	43.2	48.3
Change in plan assets:
Fair value of plan assets, beginning of year	13.3	12.9	11.4
Actual return on plan assets	0.8	1.2	0.6
Contributions	0.4	0.5	0.6
Foreign exchange effect	(0.1)	(0.5)	1.1
Benefits paid	(0.7)	(0.8)	(0.8)
Fair value of plan assets, end of year	13.7	13.3	12.9
Unfunded status	17.3	29.9	35.4
Amounts recognized in the balance sheet consist of:
Total non-current liabilities	$ 17.3	$ 29.9	$ 35.4