Derivatives (Fair Value of Derivative Assets and Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Derivatives, Fair Value [Line Items]
Fair value, derivative asset	$ 413	$ 339
Fair value, derivative liability	2,073	420
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Fair value, derivative asset	413	298
Fair value, derivative liability	1,866	420
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Fair value, derivative asset	0	41
Fair value, derivative liability	207	0
Interest Rate Agreements | Designated as Hedging Instrument | Derivative Asset
Derivatives, Fair Value [Line Items]
Fair value, derivative asset	0	298
Interest Rate Agreements | Designated as Hedging Instrument | Other Long-Term Liabilities
Derivatives, Fair Value [Line Items]
Fair value, derivative liability	1,866	0
Interest Rate Agreements | Not Designated as Hedging Instrument [Member] | Other Long-Term Liabilities
Derivatives, Fair Value [Line Items]
Fair value, derivative liability	207	0
Natural Gas Contracts | Designated as Hedging Instrument | Derivative Asset
Derivatives, Fair Value [Line Items]
Fair value, derivative asset	19	0
Natural Gas Contracts | Designated as Hedging Instrument | Prepaid and Other Current Assets
Derivatives, Fair Value [Line Items]
Fair value, derivative asset	394	0
Natural Gas Contracts | Designated as Hedging Instrument | Derivative Liability - Current
Derivatives, Fair Value [Line Items]
Fair value, derivative liability	0	420
Currency Contracts | Not Designated as Hedging Instrument [Member] | Prepaid and Other Current Assets
Derivatives, Fair Value [Line Items]
Fair value, derivative asset	$ 0	$ 41