Financial Instruments - Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$ 2,458,592	$ 2,680,674
Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	2,193,391	2,192,616
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Foreign currency cash flow hedges	0	0
Foreign Currency Contracts, Liability, Fair Value Disclosure	0	0
Derivative Liability	0	0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Foreign currency cash flow hedges	323	85
Foreign Currency Contracts, Liability, Fair Value Disclosure	208	799
Derivative Liability	22,750	22,681
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Foreign currency cash flow hedges	0	0
Foreign Currency Contracts, Liability, Fair Value Disclosure	0	0
Derivative Liability	$ 0	$ 0