| 
           Intangible Assets (Details) (USD $) 
        In Thousands, unless otherwise specified  | 
        3 Months Ended | |
|---|---|---|
| 
           Mar. 30, 2013 
         | 
        
           Dec. 31, 2012 
         | 
      |
| Summary of acquired intangible assets | ||
| Weighted Average Life | 11 years | |
| Gross Carrying Amount | $ 22,873 | $ 23,186 | 
| Accumulated Amortization | 6,817 | 6,663 | 
| 
           Patents [Member] 
         | 
        ||
| Summary of acquired intangible assets | ||
| Weighted Average Life | 12 years | |
| Gross Carrying Amount | 1,271 | 1,271 | 
| Accumulated Amortization | 809 | 784 | 
| 
           Trade Names [Member] 
         | 
        ||
| Summary of acquired intangible assets | ||
| Weighted Average Life | 10 years | |
| Gross Carrying Amount | 2,453 | 2,453 | 
| Accumulated Amortization | 210 | 162 | 
| 
           Completed and Unpatented Technology [Member] 
         | 
        ||
| Summary of acquired intangible assets | ||
| Weighted Average Life | 11 years | |
| Gross Carrying Amount | 6,377 | 6,377 | 
| Accumulated Amortization | 1,891 | 1,749 | 
| 
           Backlog and Customer Relationships [Member] 
         | 
        ||
| Summary of acquired intangible assets | ||
| Weighted Average Life | 12 years | |
| Gross Carrying Amount | 12,772 | 13,085 | 
| Accumulated Amortization | $ 3,907 | $ 3,968 |