Shareholders' Equity (Schedule Of Accumulated Other Comprehensive Income Activity) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	$ 535.0	$ 519.7
Ending Balance	591.8	535.0
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	0.5	2.3
Other comprehensive income (loss) before reclassifications, net of tax (expense) benefit	0.5	(1.8)
Amounts reclassified from accumulated other comprehensive (loss)	0.0	0.0
Net current period other comprehensive (loss) income	0.5	(1.8)
Ending Balance	1.0	0.5
Derivative (Loss) Gain [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	9.5	(9.1)
Other comprehensive income (loss) before reclassifications, net of tax (expense) benefit	(0.4)	20.2
Amounts reclassified from accumulated other comprehensive (loss)	(8.6)	(1.6)
Net current period other comprehensive (loss) income	(9.0)	18.6
Ending Balance	0.5	9.5
Pension And Postretirement Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(110.1)	(102.8)
Other comprehensive income (loss) before reclassifications, net of tax (expense) benefit	4.5	(8.1)
Amounts reclassified from accumulated other comprehensive (loss)	(0.6)	0.8
Net current period other comprehensive (loss) income	3.9	(7.3)
Ending Balance	(106.2)	(110.1)
Accumulated Other Comprehensive (Loss) Income [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(100.1)	(109.6)
Other comprehensive income (loss) before reclassifications, net of tax (expense) benefit	4.6	10.3
Amounts reclassified from accumulated other comprehensive (loss)	(9.2)	(0.8)
Net current period other comprehensive (loss) income	(4.6)	9.5
Ending Balance	$ (104.7)	$ (100.1)