Benefit Plans - Obligations and Funded Status (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Change in benefit obligations
Service cost	$ 2.8	$ 3.3	$ 2.6
Interest cost	2.0	2.9	7.3
Change in plan assets
Fair value of plan assets beginning of year	33.7
Fair value of plan assets end of year	34.4	33.7
Pension plans
Change in benefit obligations
Benefit obligation beginning of year	120.8	112.1
Service cost	2.8	3.3
Interest cost	2.0	2.9
Actuarial loss	(2.1)	9.3
Translation (gain) loss	(0.6)	1.4
Benefits paid	6.8	8.2
Benefit obligation end of year	116.1	120.8	112.1
Change in plan assets
Fair value of plan assets beginning of year	33.7	31.0
Actual return on plan assets	(0.3)	3.0
Company contributions	8.1	7.1
Translation gain (loss)	(0.3)	0.8
Benefits paid	6.8	8.2
Fair value of plan assets end of year	34.4	33.7	31.0
Funded status
Plan assets less than benefit obligation	(81.7)	(87.1)
Other post-retirement plans
Change in benefit obligations
Benefit obligation beginning of year	13.8	14.6
Service cost	0.0	0.0
Interest cost	0.2	0.4
Actuarial loss	(1.4)	0.1
Translation (gain) loss	0.0	0.0
Benefits paid	1.3	1.3
Benefit obligation end of year	11.3	13.8	14.6
Change in plan assets
Fair value of plan assets beginning of year	0.0	0.0
Actual return on plan assets	0.0	0.0
Company contributions	1.3	1.3
Translation gain (loss)	0.0	0.0
Benefits paid	1.3	1.3
Fair value of plan assets end of year	0.0	0.0	$ 0.0
Funded status
Plan assets less than benefit obligation	$ (11.3)	$ (13.8)