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Acquisitions (Schedule of Acquired Intangible Assets) (Details) - USD ($) $ in Thousands |  | 12 Months Ended
--- | --- | ---
Jun. 09, 2015 | Dec. 31, 2014
Rough Brothers Incorporated |  |
Business Acquisition [Line Items] |  |
Fair Value | $ 56,392 |
Rough Brothers Incorporated | Trademarks |  |
Business Acquisition [Line Items] |  |
Fair Value | 13,550 |
Rough Brothers Incorporated | Technology |  |
Business Acquisition [Line Items] |  |
Fair Value | 3,550 |
Rough Brothers Incorporated | Customer relationships |  |
Business Acquisition [Line Items] |  |
Fair Value | 32,892 |
Rough Brothers Incorporated | Non-compete agreements |  |
Business Acquisition [Line Items] |  |
Fair Value | 1,300 |
Rough Brothers Incorporated | Backlog |  |
Business Acquisition [Line Items] |  |
Fair Value | $ 5,100 |
Rough Brothers Incorporated | Maximum | Technology |  |
Business Acquisition [Line Items] |  |
Estimated Useful Life | 15 years |
Rough Brothers Incorporated | Maximum | Customer relationships |  |
Business Acquisition [Line Items] |  |
Estimated Useful Life | 17 years |
Rough Brothers Incorporated | Minimum | Technology |  |
Business Acquisition [Line Items] |  |
Estimated Useful Life | 7 years |
Rough Brothers Incorporated | Minimum | Customer relationships |  |
Business Acquisition [Line Items] |  |
Estimated Useful Life | 11 years |
Rough Brothers Incorporated | Minimum | Non-compete agreements |  |
Business Acquisition [Line Items] |  |
Estimated Useful Life | 5 years |
Rough Brothers Incorporated | Minimum | Backlog |  |
Business Acquisition [Line Items] |  |
Estimated Useful Life | 6 months |
2013 Acquisitions |  |
Business Acquisition [Line Items] |  |
Fair Value |  | $ 2,170
2013 Acquisitions | Trademarks |  |
Business Acquisition [Line Items] |  |
Fair Value |  | 640
2013 Acquisitions | Technology |  |
Business Acquisition [Line Items] |  |
Fair Value |  | $ 260
Estimated Useful Life |  | 15 years
2013 Acquisitions | Customer relationships |  |
Business Acquisition [Line Items] |  |
Fair Value |  | $ 1,130
Estimated Useful Life |  | 15 years
2013 Acquisitions | Non-compete agreements |  |
Business Acquisition [Line Items] |  |
Fair Value |  | $ 140
Estimated Useful Life |  | 5 years

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