Computation of Earnings Per Common Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended	12 Months Ended
Jul. 26, 2014	Apr. 26, 2014	Jan. 25, 2014	Oct. 26, 2013	Jul. 27, 2013	Apr. 27, 2013	Jan. 26, 2013	Oct. 27, 2012	Jul. 26, 2014	Jul. 27, 2013	Jul. 28, 2012
Basic earnings per unit
Net income	$ 16,489	$ 7,895	$ (3,067)	$ 18,660	$ 14,666	$ 7,199	$ 1,463	$ 11,861	$ 39,978	$ 35,188	$ 39,378
Weighted-average number of common shares (in shares)									33,773,158	33,012,595	33,653,055
Basic earnings per common share (usd per share)	$ 0.49	$ 0.23	$ (0.09)	$ 0.56	$ 0.44	$ 0.22	$ 0.04	$ 0.36	$ 1.18	$ 1.07	$ 1.17
Diluted earnings per unit
Weighted-average number of common shares (in shares)									33,773,158	33,012,595	33,653,055
Potential common stock arising from stock options, and unvested restricted share units (in shares)									1,043,223	769,592	828,840
Total shares-diluted (in shares)									34,816,381	33,782,187	34,481,895
Diluted earnings per common share (usd per share)	$ 0.47	$ 0.23	$ (0.09)	$ 0.54	$ 0.43	$ 0.21	$ 0.04	$ 0.35	$ 1.15	$ 1.04	$ 1.14
Anti-dilutive weighted shares excluded from the calculation of earnings per share (in shares)									586,389	1,204,116	1,262,964

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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