Derivative Instruments and Hedging Activities, Changes in AOCL, Net of Tax, Related to Interest Rate Swaps (Details) - USD ($) $ in Thousands	12 Months Ended
	Jul. 28, 2017	Jul. 29, 2016	Jul. 31, 2015
Changes in AOCL, net of tax, related to interest rate swaps [Roll Forward]
Balance	$ 526,443	$ 538,268	$ 528,641
Other comprehensive income (loss) before reclassifications	12,082	(6,683)	5,955
Amounts reclassified from AOCL into earnings	(2,571)	(3,332)	(4,947)
Other comprehensive income (loss), net of tax	9,511	(10,015)	1,008
Balance	544,507	526,443	538,268
Accumulated Other Comprehensive Loss [Member]
Changes in AOCL, net of tax, related to interest rate swaps [Roll Forward]
Balance	(13,740)	(3,725)	(4,733)
Balance	$ (4,229)	$ (13,740)	$ (3,725)