Retirement Benefits - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		12 Months Ended
	Sep. 30, 2025	Mar. 31, 2025	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actuarial gain on pension and other postretirement benefit obligations			$ 0.5	$ 1.4	$ 2.0
Actuarial gain (loss) on pension and postretirement benefit obligations			0.5	1.4	2.0
Fair value of plan assets			3.1	203.0
Defined contribution savings plan - expense recognized			$ 6.1	$ 5.6	4.5
Defined Contribution Savings Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Granted (in shares)			127,489	137,031
Granted (in dollars per share)			$ 39.22	$ 33.71
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Curtailment		$ 0.7	$ 0.7	$ 0.0	0.0
Contributions to fund liquidation			4.3
Settlement gain	$ 10.0		10.0	0.0	0.0
Actuarial gain (loss) on pension and postretirement benefit obligations			(3.8)	5.4
Projected benefit obligation			5.7	210.6	224.0
Fair value of plan assets			3.1	203.0	195.2
Under-funded status			2.6	7.6
Pension plans that are not fully funded - projected benefit obligation			5.7	210.6
Pension plans that are not fully funded - accumulated benefit obligation			5.4	209.2
Pension plans that are not fully funded - fair value of plan assets			3.1	203.0
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actuarial gain (loss) on pension and postretirement benefit obligations			(0.7)	1.1
Projected benefit obligation			7.4	7.2	8.7
Fair value of plan assets			0.0	0.0	$ 0.0
Under-funded status			$ 7.4	$ 7.2
Assumed health care cost trend rate, percent			7.50%
Ultimate health care cost trend rate, percent			5.00%