Derivative Financial Instruments Fair Value of Derivative Instrument (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 4,557	$ 0
Financial liabilities carried at fair value	4,806	14,195
Currency Swap [Member] | Not Designated as Hedging Instrument [Member] | Accrued expenses [Member]
Derivatives, Fair Value [Line Items]
Financial liabilities carried at fair value	0	7,170
Currency Swap [Member] | Not Designated as Hedging Instrument [Member] | Other long-term liabilities [Member]
Derivatives, Fair Value [Line Items]
Financial liabilities carried at fair value	143	0
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Accrued expenses [Member]
Derivatives, Fair Value [Line Items]
Financial liabilities carried at fair value	3,778	4,143
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Other long-term liabilities [Member]
Derivatives, Fair Value [Line Items]
Financial liabilities carried at fair value	885	2,882
Fair Value, Inputs, Level 2 [Member] | Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	4,302	0
Currency Swap [Member] | Fair Value, Inputs, Level 2 [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Financial liabilities carried at fair value	143	7,170
Currency Swap [Member] | Fair Value, Inputs, Level 2 [Member] | Not Designated as Hedging Instrument [Member] | Prepaid expenses and other [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	255	0
Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Financial liabilities carried at fair value	$ 4,663	$ 7,025