Financial Instruments (Estimated Fair Value Of Financial Instruments) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Financial Instruments [Abstract]
Total debt, including current portion, Carrying amount	$ (1,070.1)	$ (1,071.0)
Total debt, including current portion, Estimated Fair Value	(1,076.4)	(1,075.9)
Foreign currency contract obligations, Carrying amount	(0.5)	(1.8)
Foreign currency contract obligations, Estimated Fair Value	(0.5)	(1.8)
Natural gas contracts, Carrying amount	(0.2)	(2.7)
Natural gas contracts, Estimated Fair Value	(0.2)	(2.7)
Interest rate swap contracts, Carrying amount	(23.2)	(25.7)
Interest rate swap contracts, Estimated Fair Value	$ (23.2)	$ (25.7)