Shareholders' Equity, Summary of Changes in AOCIL, Net of Tax (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Apr. 27, 2018	Apr. 28, 2017	Apr. 27, 2018	Apr. 28, 2017
Changes in AOCIL, net of tax, related to interest rate swaps [Roll Forward]
Balance, beginning of period	[1]			$ 544,507
Other comprehensive income before reclassifications				10,661
Amounts reclassified from AOCIL				(1,981)
Other comprehensive income (loss), net of tax		$ 3,254	$ (1,095)	8,680	$ 9,712
Balance, end of period		640,381		640,381
Accumulated Other Comprehensive Income (Loss) [Member]
Changes in AOCIL, net of tax, related to interest rate swaps [Roll Forward]
Balance, beginning of period				(4,229)
Balance, end of period		$ 4,451		$ 4,451

[1] This Condensed Consolidated Balance Sheet has been derived from the audited Consolidated Balance Sheet as of July 28, 2017, as filed with the Securities and Exchange Commission in the Company's Annual Report on Form 10-K for the fiscal year ended July 28, 2017.