Derivative Financial Instruments (Summary of Fair Value of Derivative Instruments on Consolidated Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Derivative Assets, Fair Value	$ 8.9	$ 9.7
Derivative Liabilities, Fair Value	1.4	0.5
Other Current Assets [Member] | Natural Gas Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets, Fair Value		1.0
Other Current Assets [Member] | Foreign Exchange Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets, Fair Value		1.2
Other Current Assets [Member] | Interest Rate Swap Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets, Fair Value	0.2
Other Non-Current Assets [Member] | Foreign Exchange Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets, Fair Value		0.1
Other Non-Current Assets [Member] | Interest Rate Swap Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets, Fair Value	8.7	7.4
Accounts Payable And Accrued Expenses [Member] | Natural Gas Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities, Fair Value	0.5
Accounts Payable And Accrued Expenses [Member] | Foreign Exchange Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities, Fair Value	0.7
Other Long-Term Liabilities [Member] | Natural Gas Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities, Fair Value	0.1
Other Long-Term Liabilities [Member] | Foreign Exchange Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities, Fair Value	$ 0.1
Other Long-Term Liabilities [Member] | Interest Rate Swap Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities, Fair Value		$ 0.5