Derivative Financial Instruments - Effect of Interest Rate Contracts and Interest Rate Swaps on Consolidated Statements of Income and Other Comprehensive Income (Details) - Interest Rate Swap [Member] - Other Comprehensive Income [Member] - USD ($) $ in Thousands	12 Months Ended
	Apr. 29, 2017	Apr. 30, 2016	Apr. 25, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Effect of interest rate contracts	$ 0	$ 0	$ (23,343)
Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Effect of interest rate contracts	$ (2,802)	$ (2,817)	$ (56)