Employee Benefit Plans (Details) (USD $)	12 Months Ended
	Jul. 27, 2013		Jul. 28, 2012		Jul. 30, 2011
Multiemployer Plans [Line Items]
Multiemployer plan contributions	$ 3,205,000		$ 2,882,000		$ 3,811,000
Contributions by employer	800,000
Maximum annual contribution per employee	15.00%
Employer matching contribution	30.00%
Employer matching contribution percent	5.00%
Company contributions	1,600,000		1,200,000		1,000,000
Pension Hospitalization and Benefit Plan of the Electric Industry-Pension Trust Fund
Multiemployer Plans [Line Items]
Multiemployer plan contributions	2,962,000		2,882,000		3,811,000
Other Multiemployer Plans
Multiemployer Plans [Line Items]
Multiemployer plan contributions	$ 243,000	[1]	$ 0	[1]	$ 0	[1]

[1] As a result of the acquisition of the Acquired Subsidiaries, the Company contributes to various multiemployer plans for employees of certain of the Acquired Subsidiaries. Contribution requirements to these multiemployer plans are specified in the applicable collective bargaining agreements, and are typically assessed on a pay-as-you-go basis based on union employee payrolls, which vary depending on location and union resources needed in connection with certain projects.