Fair Value Measurements Fair Value of Financial Instruments not carried at Fair Value (Details) (USD $) In Thousands, unless otherwise specified	Jun. 28, 2013	Dec. 31, 2012
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument, Fair Value Disclosure	$ 295,129	$ 259,585
Portion at Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument, Fair Value Disclosure	314,187	287,595
Fair Value, Inputs, Level 1 [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument, Fair Value Disclosure	106,165	105,260
Fair Value, Inputs, Level 1 [Member] | Portion at Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument, Fair Value Disclosure	138,907	144,460
Fair Value, Inputs, Level 2 [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument, Fair Value Disclosure	188,964	154,325
Fair Value, Inputs, Level 2 [Member] | Portion at Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument, Fair Value Disclosure	$ 175,280	$ 143,135