Accumulated Other Comprehensive Loss (Changes In Accumlated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance			$ 930.5
Retained Earnings	$ 838.7		838.7		$ 725.1
Ending balance	1,065.1		1,065.1
Amounts reclassified from accumulated other comprehensive loss, tax	(2.2)	$ (2.0)	(4.5)	$ (3.9)
Foreign Currency
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(3.7)	(16.6)	(5.1)	(7.7)
Other comprehensive income before reclassifications	2.0	3.9	3.4	(5.0)
Amounts reclassified from accumulated other comprehensive loss (net of tax $(2.3) and $(1.9))
Net current-period other comprehensive income (loss)	2.0	3.9	3.4	(5.0)
Ending balance	(1.7)	(12.7)	(1.7)	(12.7)
Pension and Other Postretirement Benefits
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(235.0)	(237.4)	(241.6)	(242.9)
Other comprehensive income before reclassifications
Amounts reclassified from accumulated other comprehensive loss (net of tax $(2.3) and $(1.9))	6.2	5.7	12.8	11.2
Net current-period other comprehensive income (loss)	6.2	5.7	12.8	11.2
Ending balance	(228.8)	(231.7)	(228.8)	(231.7)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(238.7)	(254.0)	(246.7)	(250.6)
Other comprehensive income before reclassifications	2.0	3.9	3.4	(5.0)
Amounts reclassified from accumulated other comprehensive loss (net of tax $(2.3) and $(1.9))	6.2	5.7	12.8	11.2
Net current-period other comprehensive income (loss)	8.2	9.6	16.2	6.2
Ending balance	$ (230.5)	$ (244.4)	$ (230.5)	$ (244.4)