Debt (Details) - Revolving Credit Facility [Member] $ in Thousands	9 Months Ended
	Apr. 28, 2017 USD ($)	Jul. 29, 2016 USD ($)
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 750,000
Line of credit facility, expiration date	Jan. 08, 2020
Outstanding borrowings	$ 400,000	$ 400,000
Amount of standby letters of credit	9,655
Current borrowing capacity	$ 340,345
Weighted average interest rates of swapped debt	2.85%
Restrictions on dividends payable	Under the Revolving Credit Facility, provided there is no default existing and the total of the Company’s availability under the Revolving Credit Facility plus the Company’s cash and cash equivalents on hand is at least $100,000 (the “cash availability”), the Company may declare and pay cash dividends on shares of its common stock and repurchase shares of its common stock (1) in an unlimited amount if, at the time such dividend or repurchase is made, the Company’s consolidated total leverage ratio is 3.00 to 1.00 or less and (2) in an aggregate amount not to exceed $100,000 in any fiscal year if the Company’s consolidated total leverage ratio is greater than 3.00 to 1.00 at the time the dividend or repurchase is made; notwithstanding (1) and (2), so long as immediately after giving effect to the payment of any such dividends, cash availability is at least $100,000, the Company may declare and pay cash dividends on shares of its common stock in an aggregate amount not to exceed in any fiscal year the product of the aggregate amount of dividends declared in the fourth quarter of the immediately preceding fiscal year multiplied by four.
Liquidity requirements	$ 100,000
Dividends threshold	$ 100,000
Leverage ratio, maximum	3.00
Multiplier used in calculating aggregate amount of cash dividends on shares of common stock in any fiscal year	4