Shareholders' Equity (Schedule of Accumulated Other Comprehensive Income (Loss) Activity (Details) - USD ($) $ in Millions		3 Months Ended			9 Months Ended
		Sep. 30, 2025	Sep. 30, 2024		Sep. 30, 2025		Sep. 30, 2024
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		$ 837.8	$ 669.0		$ 757.1		$ 591.8
Ending Balance		889.2	717.0		889.2		717.0
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	[1]	(0.4)	(0.2)		(2.2)		1.0
Other comprehensive income (loss) before reclassifications, net of tax (expense) benefit	[1]	(0.9)	0.3		0.9		(0.9)
Amounts reclassified from accumulated other comprehensive (loss)	[1]	0.0	0.0		0.0		0.0
Net current period other comprehensive income (loss)	[1]	(0.9)	0.3		0.9		(0.9)
Ending Balance	[1]	(1.3)	0.1		(1.3)		0.1
Derivative Gain (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	[1],[2]	(2.9)	1.2		(1.1)		0.5
Other comprehensive income (loss) before reclassifications, net of tax (expense) benefit	[1],[2]	0.1	(4.7)		(1.4)		(1.4)
Amounts reclassified from accumulated other comprehensive (loss)	[1],[2]	(0.1)	(1.0)		(0.4)		(3.6)
Net current period other comprehensive income (loss)	[1],[2]	0.0	(5.7)		(1.8)		(5.0)
Ending Balance	[1],[2]	(2.9)	(4.5)		(2.9)		(4.5)
Pension And Postretirement Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	[1]	(105.6)	(107.5)	[2]	(106.9)	[2]	(106.2)	[2]
Other comprehensive income (loss) before reclassifications, net of tax (expense) benefit	[1]	0.0	(0.4)	[2]	0.0	[2]	(0.4)	[2]
Amounts reclassified from accumulated other comprehensive (loss)	[1]	0.6	(0.6)	[2]	1.9	[2]	(1.9)	[2]
Net current period other comprehensive income (loss)	[1]	0.6	(1.0)	[2]	1.9	[2]	(2.3)	[2]
Ending Balance	[1],[2]	(105.0)	(108.5)		(105.0)		(108.5)
Accumulated Other Comprehensive (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	[1],[2]	(108.9)	(106.5)		(110.2)		(104.7)
Other comprehensive income (loss) before reclassifications, net of tax (expense) benefit	[1],[2]	(0.8)	(4.8)		(0.5)		(2.7)
Amounts reclassified from accumulated other comprehensive (loss)	[1],[2]	0.5	(1.6)		1.5		(5.5)
Net current period other comprehensive income (loss)	[1],[2]	(0.3)	(6.4)		1.0		(8.2)
Ending Balance	[1],[2]	$ (109.2)	$ (112.9)		$ (109.2)		$ (112.9)

[1] Amounts are net of tax.

[2] Amounts include our 50% share of AOCL components from our WAVE joint venture.