Quarterly Financial Data (Unaudited) Quarterly Financial Data (Unaudited) (Details) (USD $)	3 Months Ended								12 Months Ended
	Jul. 27, 2013	Apr. 27, 2013	Jan. 26, 2013	Oct. 27, 2012	Jul. 28, 2012	Apr. 28, 2012	Jan. 28, 2012	Oct. 29, 2011	Jul. 27, 2013	Jul. 28, 2012	Jul. 30, 2011
Effect of Fourth Quarter Events [Line Items]
Revenues	$ 478,632,000	$ 437,367,000	$ 369,326,000	$ 323,286,000	$ 318,034,000	$ 296,103,000	$ 267,407,000	$ 319,575,000	$ 1,608,612,000	$ 1,201,119,000	$ 1,035,868,000
Cost of earned revenues, excluding depreciation and amortization	384,169,000	357,664,000	301,516,000	257,066,000	252,137,000	241,386,000	220,239,000	255,187,000	1,300,416,000	968,949,000	837,119,000
Gross profit	94,463,000	79,703,000	67,810,000	66,220,000	65,897,000	54,717,000	47,168,000	64,388,000
Net income	14,666,000	7,199,000	1,463,000	11,861,000	13,282,000	9,645,000	3,485,000	12,966,000	35,188,000	39,378,000	16,107,000
Earnings per common share - Basic	$ 0.44	$ 0.22	$ 0.04	$ 0.36	$ 0.40	$ 0.29	$ 0.10	$ 0.39	$ 1.07	$ 1.17	$ 0.46
Earnings per common share - Diluted	$ 0.43	$ 0.21	$ 0.04	$ 0.35	$ 0.39	$ 0.28	$ 0.10	$ 0.38	$ 1.04	$ 1.14	$ 0.45
Sage Telecommunications Corp of Colorado, LLC
Effect of Fourth Quarter Events [Line Items]
Acquisition related costs	$ 200,000		$ 6,500,000						$ 200,000