Derivative Financial Instruments (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended		12 Months Ended				12 Months Ended					12 Months Ended			12 Months Ended
	Dec. 31, 2012 Natural Gas Commodity Contracts [Member]	Dec. 31, 2011 Natural Gas Commodity Contracts [Member]	Dec. 31, 2012 Interest Rate Swap Contracts [Member]	Mar. 27, 2012 Interest Rate Swap Contracts [Member]	Feb. 27, 2012 Interest Rate Swap Contracts [Member]	Mar. 31, 2011 Interest Rate Swap Contracts [Member] contract	Dec. 31, 2012 Forward Interest Rate Swap [Member]	Mar. 27, 2012 Forward Interest Rate Swap [Member]	Mar. 31, 2011 Term Loan A [Member] Interest Rate Swap Contracts [Member]	Dec. 31, 2012 Term Loan B [Member]	Mar. 31, 2011 Term Loan B [Member] Interest Rate Swap Contracts [Member]	Dec. 31, 2012 Foreign Exchange Contracts [Member] Sales And Purchases [Member]	Dec. 31, 2011 Foreign Exchange Contracts [Member] Sales And Purchases [Member]	Dec. 31, 2011 Foreign Exchange Contracts [Member] Intercompany Loans And Dividends [Member]	Dec. 31, 2011 Not Designated As Hedging Instrument [Member]
Derivative [Line Items]
Maximum length of time hedged in cash flow hedge	24 months											15 months
Notional amount	$ 21.5	$ 47.2		$ 250.0				$ 200.0	$ 100.0		$ 200.0	$ 129.7	$ 128.3	$ 21.8
Number of interest rate swaps entered during the quarter						2
Derivative, maturity date			Mar. 01, 2018
LIBOR floor										1.00%
Fixed interest rate					1.9275%			2.81%
Derivative, maturity date range, start							Nov. 01, 2015
Derivative, maturity date range, end							Mar. 01, 2018
Gain (loss) recognized in income for derivative instruments															$ 4.7