Costs and Estimated Earnings in Excess of Billings (Details) (USD $) In Thousands, unless otherwise specified	Apr. 27, 2013	Jul. 28, 2012
Contractors [Abstract]
Costs incurred on contracts in progress	$ 174,089	$ 100,766
Estimated to date earnings	40,644	26,555
Total costs and estimated earnings	214,733	127,321
Less: billings to date	(43,183)	(1,522)
Total costs in excess of billings	171,550	125,799
Costs and estimated earnings in excess of billings	183,920	127,321
Billings in excess of costs and estimated earnings	$ 12,370	$ 1,522

Liability attributable to (i) billings in excess of costs under the percentage of completion contract accounting method representing the difference between contractually invoiced amounts (billings) and revenue recognized based, for example, on costs incurred to estimated total costs at period end or (ii) contractually invoiced amounts (billings) in excess of costs incurred and accumulated under the completed contract accounting method that are expected to be realized within one year or one operating cycle, whichever is longer, from the reporting date.

+ References+ Details

Total amount included in cost of uncompleted contracts in excess of related billings, or unbilled accounts receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.3(c)(3))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 912

-SubTopic 310

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6471842&loc=d3e55302-109406

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 35

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6802688&loc=d3e57807-111642

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

-Number 43

-Section A

-Paragraph 4, 21

-Chapter 11

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 35

-Section 45

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6802688&loc=d3e57795-111642

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

-Number 45

-Paragraph 12

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 3

-Subparagraph c(2), c(3), c(4)

-Article 5

+ Details

- Definition

Amount included in cost of uncompleted contracts in excess of related billings, or unbilled accounts receivable, which is expected to be collected within a year within one year (or one operating cycle, if longer) from the date of the balance sheet.

+ References+ Details