Shareholders' Equity, Summary of Changes in AOCL, Net of Tax (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Apr. 28, 2017	Apr. 29, 2016	Apr. 28, 2017	Apr. 29, 2016
Changes in AOCL, net of tax, related to interest rate swaps [Roll Forward]
Balance, beginning of period	[1]			$ 526,443
Other comprehensive income before reclassifications				11,783
Amounts reclassified from AOCL				(2,071)
Other comprehensive income (loss), net of tax		$ (1,095)	$ (975)	9,712	$ (7,125)
Balance, end of period		601,960		601,960
Accumulated Other Comprehensive Loss [Member]
Changes in AOCL, net of tax, related to interest rate swaps [Roll Forward]
Balance, beginning of period				(13,740)
Balance, end of period		$ (4,028)		$ (4,028)

[1] This Condensed Consolidated Balance Sheet has been derived from the audited Consolidated Balance Sheet as of July 29, 2016, as filed with the Securities and Exchange Commission in the Company's Annual Report on Form 10-K for the fiscal year ended July 29, 2016.