Commitments and Contingencies	9 Months Ended
Apr. 23, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies In May 2013, CertusView Technologies, LLC (“CertusView”), a wholly-owned subsidiary of the Company, filed suit against S & N Communications, Inc. and S & N Locating Services, LLC in the United States District Court for the Eastern District of Virginia alleging infringement of certain United States patents. In January 2015, the District Court granted defendants’ motion for judgment on the pleadings for failure to claim patent-eligible subject matter, and entered final judgment on those claims the same day. CertusView filed a Notice of Appeal in February 2015 with the Court of Appeals for the Federal Circuit. In May 2015, the District Court re-opened the case to allow defendants to proceed with inequitable conduct counterclaims. In July 2015, the Court of Appeals dismissed the appeal in that court pending resolution of proceedings in the District Court. A bench trial in the District Court on the inequitable conduct counterclaims whereby defendants are seeking additional grounds to find the patents unenforceable took place in March 2016 and post-trial briefs were filed with the District Court on April 22, 2016. An unfavorable outcome for the inequitable conduct counterclaims may result in an award of attorneys’ fees, costs, and expenses. The Company believes the counterclaims to be without merit and intends to vigorously defend itself against these counterclaims and appeal the District Court’s ruling with respect to the patent-eligible subject matter. From time to time, the Company is party to various other claims and legal proceedings. It is the opinion of management, based on information available at this time, that such other pending claims or proceedings will not have a material effect on its financial statements. For claims within the Company’s insurance program, it retains the risk of loss, up to certain limits, for matters related to automobile liability, general liability (including damages associated with underground facility locating services), workers’ compensation, and employee group health. The Company has established reserves that it believes to be adequate based on current evaluations and experience with these types of claims. For these claims, the effect on the Company’s financial statements is generally limited to the amount needed to satisfy insurance deductibles or retentions. Commitments Performance Bonds and Guarantees - The Company has obligations under performance and other surety contract bonds related to certain of its customer contracts. Performance bonds generally provide a customer with the right to obtain payment and/or performance from the issuer of the bond if the Company fails to perform its contractual obligations. As of April 23, 2016 and July 25, 2015, the Company had $242.0 million and $294.9 million of outstanding performance and other surety contract bonds, respectively. The Company periodically guarantees certain obligations of its subsidiaries, including obligations in connection with obtaining state contractor licenses and leasing real property and equipment. Letters of Credit - The Company has standby letters of credit issued under its Credit Agreement as part of its insurance program. These standby letters of credit collateralize the Company’s obligations to its insurance carriers in connection with the settlement of potential claims. As of April 23, 2016 and July 25, 2015, the Company had $57.7 million and $54.4 million, respectively, of outstanding standby letters of credit issued under the Credit Agreement.

Commitments and Contingencies

In May 2013, CertusView Technologies, LLC (“CertusView”), a wholly-owned subsidiary of the Company, filed suit against S & N Communications, Inc. and S & N Locating Services, LLC in the United States District Court for the Eastern District of Virginia alleging infringement of certain United States patents. In January 2015, the District Court granted defendants’ motion for judgment on the pleadings for failure to claim patent-eligible subject matter, and entered final judgment on those claims the same day. CertusView filed a Notice of Appeal in February 2015 with the Court of Appeals for the Federal Circuit. In May 2015, the District Court re-opened the case to allow defendants to proceed with inequitable conduct counterclaims. In July 2015, the Court of Appeals dismissed the appeal in that court pending resolution of proceedings in the District Court. A bench trial in the District Court on the inequitable conduct counterclaims whereby defendants are seeking additional grounds to find the patents unenforceable took place in March 2016 and post-trial briefs were filed with the District Court on April 22, 2016. An unfavorable outcome for the inequitable conduct counterclaims may result in an award of attorneys’ fees, costs, and expenses. The Company believes the counterclaims to be without merit and intends to vigorously defend itself against these counterclaims and appeal the District Court’s ruling with respect to the patent-eligible subject matter.

From time to time, the Company is party to various other claims and legal proceedings. It is the opinion of management, based on information available at this time, that such other pending claims or proceedings will not have a material effect on its financial statements.

For claims within the Company’s insurance program, it retains the risk of loss, up to certain limits, for matters related to automobile liability, general liability (including damages associated with underground facility locating services), workers’ compensation, and employee group health. The Company has established reserves that it believes to be adequate based on current evaluations and experience with these types of claims. For these claims, the effect on the Company’s financial statements is generally limited to the amount needed to satisfy insurance deductibles or retentions.

Commitments

Performance Bonds and Guarantees - The Company has obligations under performance and other surety contract bonds related to certain of its customer contracts. Performance bonds generally provide a customer with the right to obtain payment and/or performance from the issuer of the bond if the Company fails to perform its contractual obligations. As of April 23, 2016 and July 25, 2015, the Company had $242.0 million and $294.9 million of outstanding performance and other surety contract bonds, respectively.

The Company periodically guarantees certain obligations of its subsidiaries, including obligations in connection with obtaining state contractor licenses and leasing real property and equipment.

Letters of Credit - The Company has standby letters of credit issued under its Credit Agreement as part of its insurance program. These standby letters of credit collateralize the Company’s obligations to its insurance carriers in connection with the settlement of potential claims. As of April 23, 2016 and July 25, 2015, the Company had $57.7 million and $54.4 million, respectively, of outstanding standby letters of credit issued under the Credit Agreement.