Accumulated Other Comprehensive Loss (Changes In Accumlated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ 930.5
Retained Earnings	765.4		$ 725.1
Ending balance	985.6
Amounts reclassified from accumulated other comprehensive loss, tax	(2.3)	$ (1.9)
Foreign Currency
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(5.1)	(7.7)
Other comprehensive income before reclassifications	1.4	(8.9)
Amounts reclassified from accumulated other comprehensive loss (net of tax $(2.3) and $(1.9))
Net current-period other comprehensive income (loss)	1.4	(8.9)
Ending balance	(3.7)	(16.6)
Pension and Other Postretirement Benefits
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(241.6)	(242.9)
Other comprehensive income before reclassifications
Amounts reclassified from accumulated other comprehensive loss (net of tax $(2.3) and $(1.9))	6.6	5.5
Net current-period other comprehensive income (loss)	6.6	5.5
Ending balance	(235.0)	(237.4)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(246.7)	(250.6)
Other comprehensive income before reclassifications	1.4	(8.9)
Amounts reclassified from accumulated other comprehensive loss (net of tax $(2.3) and $(1.9))	6.6	5.5
Net current-period other comprehensive income (loss)	8.0	(3.4)
Ending balance	$ (238.7)	$ (254.0)