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Basis of Presentation and Accounting Policies - Segment (Details) (USD $) In Thousands, unless otherwise specified | 3 Months Ended
--- | ---
Oct. 25, 2014 subsidiary segment | Oct. 26, 2013
Segment Reporting Information [Line Items] |  |
Number of reportable segments | 1 |
Number of subsidiaries | 2 |
Contract revenues | $ 510,389 | $ 512,720
Canada |  |
Segment Reporting Information [Line Items] |  |
Contract revenues | $ 4,700 | $ 3,300

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- Definition Aggregate revenue during the period from services rendered in the normal course of business, after deducting allowances and discounts. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1(d)) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Article 5 + Details
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