Shareholders' Equity, Summary of Changes in AOCL, Net of Tax (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jan. 27, 2017	Jan. 29, 2016	Jan. 27, 2017	Jan. 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				12,265
Amounts reclassified from AOCL				(1,458)
Other comprehensive income (loss), net of tax		$ 7,036	$ (3,117)	10,807	$ (6,150)
Balance, end of period		581,717		581,717
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		$ (2,933)		$ (2,933)

[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.