Accumulated Other Comprehensive Loss - Changes in accumulated other comprehensive loss (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Dec. 31, 2025	Mar. 31, 2025	Dec. 31, 2024
Accumulated Other Comprehensive Income (Loss) [Line Items]
Equity, Including Portion Attributable to Noncontrolling Interest	$ 1,145.7	$ 1,145.3	$ 1,299.7	$ 1,307.2
Changes in accumulated other comprehensive loss
Other comprehensive income, net of tax, before reclassifications	7.4
Amounts reclassified from AOCI, net of tax expense of $0.7, $—, and $0.7	(2.2)
Reclassification from AOCI, Current Period, Tax	(0.7)
Other comprehensive income	5.2
Unrealized gains/(losses) on derivative financial instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Equity, Including Portion Attributable to Noncontrolling Interest	2.4	(2.8)
Changes in accumulated other comprehensive loss
Other comprehensive income, net of tax, before reclassifications	7.4
Amounts reclassified from AOCI, net of tax expense of $0.7, $—, and $0.7	(2.2)
Reclassification from AOCI, Current Period, Tax	(0.7)
Other comprehensive income	5.2
Net actuarial gains/(losses) of defined benefit plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Equity, Including Portion Attributable to Noncontrolling Interest	(1.4)	(1.4)
Changes in accumulated other comprehensive loss
Other comprehensive income, net of tax, before reclassifications	0.0
Amounts reclassified from AOCI, net of tax expense of $0.7, $—, and $0.7	0.0
Reclassification from AOCI, Current Period, Tax	0.0
Other comprehensive income	0.0
Accumulated other comprehensive income (loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Equity, Including Portion Attributable to Noncontrolling Interest	$ 1.0	$ (4.2)	$ (4.2)	$ (4.2)