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Acquisitions (Details) $ in Millions | 3 Months Ended
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Oct. 24, 2015 USD ($) | Jul. 25, 2015 USD ($) | Oct. 25, 2014 USD ($) business
TelCom Construction, Inc. |  |  |
Business Acquisition [Line Items] |  |  |
Payment to acquire business, net of cash acquired | $ 48.8 |  |
Hewitt Power & Communications, Inc |  |  |
Business Acquisition [Line Items] |  |  |
Payment to acquire business, net of cash acquired |  |  | $ 8.0
Cable Installation Contractors |  |  |
Business Acquisition [Line Items] |  |  |
Payment to acquire business, net of cash acquired |  |  | $ 1.5
Number of businesses acquired | business |  |  | 2
Moll's Utility Services, LLC |  |  |
Business Acquisition [Line Items] |  |  |
Payment to acquire business, net of cash acquired |  | $ 6.5 |
Venture Communications Group, LLC |  |  |
Business Acquisition [Line Items] |  |  |
Payment to acquire business, net of cash acquired |  | $ 15.6 |

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- Definition The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Investing Activities -URI http://asc.fasb.org/extlink&oid=6516133 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3213-108585 + Details
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