Contractual interest rate for funds borrowed, under the debt agreement.

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The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. This element is for unclassified presentations; for classified presentations there is a separate and distinct element.

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Basis of Presentation and Accounting Policies (Details) (USD $)	3 Months Ended		6 Months Ended
	Jan. 25, 2014	Jan. 26, 2013	Jan. 25, 2014	Jan. 26, 2013	Jul. 27, 2013
Debt Instrument [Line Items]
Contract revenues	$ 390,518,000	$ 369,326,000	$ 903,238,000	$ 692,613,000
Restricted cash	4,000,000		4,000,000		3,700,000
Senior Subordinated Notes \| 7.125% Senior Subordinated Notes Due 2021
Debt Instrument [Line Items]
Debt, interest rate (in percent)	0.00%		0.00%		7.125%
Canada
Debt Instrument [Line Items]
Contract revenues	$ 2,100,000	$ 2,500,000	$ 5,400,000	$ 6,400,000