Derivative Instruments and Hedging Activities, Estimated Fair Values of Derivative Instruments (Details) - Interest Rate Swaps [Member] - USD ($) $ in Thousands		Apr. 27, 2018	Jul. 28, 2017
Derivatives, Fair Value [Line Items]
Fair value, asset	[1]	$ 5,968	$ 32
Fair value, liability	[1]	37	6,880
Prepaid Expenses and Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value, asset	[1]	5	32
Other Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value, asset	[1]	5,963	0
Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value, liability	[1]	0	47
Other Long-Term Obligations [Member]
Derivatives, Fair Value [Line Items]
Fair value, liability	[1]	$ 37	$ 6,833

[1] These interest rate swap assets and liabilities are recorded at gross at both April 27, 2018 and July 28, 2017 since there were no offsetting assets and liabilities under the Company's master netting agreements.