Derivative Instruments and Hedging Activities, Pre-Tax Effects of Derivative Instruments on AOCL and Income (Details) - Interest Rate Swaps [Member] - Cash Flow Hedging [Member] - USD ($) $ in Thousands	12 Months Ended
	Jul. 28, 2017	Jul. 29, 2016	Jul. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Amount of income (loss) recognized in AOCL on derivatives (effective portion)	$ 15,402	$ (16,188)	$ 1,641
Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of loss reclassified from AOCL into income (effective portion)	$ 4,163	$ 5,395	$ 8,052