Acquisitions (Details) (USD $)	3 Months Ended					3 Months Ended				0 Months Ended			0 Months Ended
	Oct. 26, 2013	Oct. 27, 2012	Jul. 27, 2013	Dec. 03, 2012	Dec. 03, 2012 Quanta Services, Inc.	Oct. 26, 2013 Sage Telecommunications Corp of Colorado, LLC	Oct. 26, 2013 Businesses Acquired in Fiscal 2013	Oct. 26, 2013 Senior Loan and Revolving Credit Credit Agreement, December 3, 2012, Maturing December 2017	Dec. 03, 2012 Senior Loan and Revolving Credit Credit Agreement, December 3, 2012, Maturing December 2017	Dec. 12, 2012 Senior Subordinated Notes 7.125% Senior Subordinated Notes Due 2021	Oct. 26, 2013 Senior Subordinated Notes 7.125% Senior Subordinated Notes Due 2021	Jul. 27, 2013 Senior Subordinated Notes 7.125% Senior Subordinated Notes Due 2021	Dec. 12, 2012 Senior Subordinated Notes 7.125% Senior Subordinated Notes Due 2021 Dycom Investments, Inc.
Business Acquisition [Line Items]
Cash paid					$ 275,000,000
Estimated adjustment for working capital received in excess of target amount					40,400,000
Amount paid for other specified items					3,700,000
Credit facility amount									400,000,000
Proceeds from issuance of long-term debt										90,000,000			90,000,000
Debt, interest rate (in percent)											7.125%	7.125%
Repayments of credit facility								90,000,000
Number of states in which entity operates				50
Acquisition payments						11,300,000
Goodwill	267,810,000		267,810,000	87,900,000		5,000,000
Carrying amount				90,600,000
Revenues							150,300,000
Amortization expense for finite-lived intangible assets	5,200,000	1,600,000					3,400,000
Operating Income (Loss)							$ 4,200,000