Shareholders' Equity (Schedule of Accumulated Other Comprehensive (Loss) Activity) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2023	Mar. 31, 2022
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		$ 535.0	$ 519.7
Ending Balance		544.8	537.6
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		0.5	2.3
Other comprehensive income before reclassifications, net of tax (expense)		(0.1)	0.7
Amounts reclassified from accumulated other comprehensive (loss)		0.0	0.0
Net current period other comprehensive income		(0.1)	0.7
Ending Balance		0.4	3.0
Derivative (Loss) Gain [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	[1]	9.5	(9.1)
Other comprehensive income before reclassifications, net of tax (expense)	[1]	(0.3)	12.3
Amounts reclassified from accumulated other comprehensive (loss)	[1]	(1.9)	(1.7)
Net current period other comprehensive income	[1]	(2.2)	10.6
Ending Balance	[1]	7.3	1.5
Pension And Postretirement Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	[1]	(110.1)	(102.8)
Other comprehensive income before reclassifications, net of tax (expense)	[1]	0.4	0.5
Amounts reclassified from accumulated other comprehensive (loss)	[1]	(0.2)	0.1
Net current period other comprehensive income	[1]	0.2	0.6
Ending Balance	[1]	(109.9)	(102.2)
Accumulated Other Comprehensive (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	[1]	(100.1)	(109.6)
Other comprehensive income before reclassifications, net of tax (expense)	[1]	0.0	13.5
Amounts reclassified from accumulated other comprehensive (loss)	[1]	(2.1)	(1.6)
Net current period other comprehensive income	[1]	(2.1)	11.9
Ending Balance	[1]	$ (102.2)	$ (97.7)

[1] Amounts are net of tax