Pensions and Postretirement Benefits - Summary of Change in Defined Benefit and Postretirement Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Change in plan assets
Fair value of plan assets at beginning of year	$ 161.3
Fair value of plan assets at end of year	169.9	$ 161.3
Funded (underfunded) status of the plans
Pension assets	86.2	74.8
Pension Benefits
Change in benefit obligation
Benefit obligation at beginning of year	86.5	79.4
Service costs	4.2	4.1	$ 3.8
Interest costs	1.4	2.1	2.6
Actuarial (gains) losses	(2.5)	6.6
Benefits and expenses paid	(5.9)	(5.7)
Benefit obligation at end of year	83.7	86.5	79.4
Change in plan assets
Fair value of plan assets at beginning of year	161.3	144.4
Actual return on plan assets	19.6	23.2
Company contributions	0.0	0.0
Cash transfer to fund postretirement benefit payments	(5.1)	(0.6)
Benefits and expenses paid	(5.9)	(5.7)
Fair value of plan assets at end of year	169.9	161.3	144.4
Funded (underfunded) status of the plans	86.2	74.8
Funded (underfunded) status of the plans
Pension assets	86.2	74.8
Other current liabilities	0.0	0.0
Other long-term liabilities	0.0	0.0
Asset, defined benefit plan	86.2	74.8
Amounts recognized in Accumulated other comprehensive loss
Net actuarial loss	10.8	21.3
Net prior service cost	0.2	0.2
Accumulated other comprehensive loss	11.0	21.5
Postretirement Benefits
Change in benefit obligation
Benefit obligation at beginning of year	7.9	8.0
Service costs	0.0	0.0	0.0
Interest costs	0.1	0.2	0.3
Actuarial (gains) losses	(0.5)	0.6
Benefits and expenses paid	(0.6)	(0.9)
Benefit obligation at end of year	6.9	7.9	8.0
Change in plan assets
Fair value of plan assets at beginning of year	0.0	0.0
Actual return on plan assets	0.0	0.0
Company contributions	5.1	0.9
Cash transfer to fund postretirement benefit payments	0.0	0.0
Benefits and expenses paid	(0.6)	(0.9)
Fair value of plan assets at end of year	4.5	0.0	$ 0.0
Funded (underfunded) status of the plans	(2.4)	(7.9)
Funded (underfunded) status of the plans
Pension assets	0.0	0.0
Other current liabilities	0.1	0.8
Other long-term liabilities	2.3	7.1
Liability, defined benefit plan	2.4	7.9
Amounts recognized in Accumulated other comprehensive loss
Net actuarial loss	2.2	3.0
Net prior service cost	0.0	0.0
Accumulated other comprehensive loss	$ 2.2	$ 3.0