Assets and liabilities measured at fair value (Details) $ in Thousands	Apr. 29, 2016 USD ($)
Reported amount | Current portion of long-term debt obligations
Liabilities:
Long-term obligations	$ 1,526
Reported amount | Long-term obligations
Liabilities:
Long-term obligations	2,989,663
Reported amount | Accrued expenses and other current liabilities
Liabilities:
Deferred compensation	7,581
Reported amount | Noncurrent Other liabilities
Liabilities:
Deferred compensation	16,321
Fair value measurements on recurring basis | Balance at the end of the period
Liabilities:
Long-term obligations	3,073,459
Deferred compensation	23,902
Fair value measurements on recurring basis | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1)
Liabilities:
Long-term obligations	2,362,560
Deferred compensation	23,902
Fair value measurements on recurring basis | Significant Other Observable Inputs (Level 2)
Liabilities:
Long-term obligations	$ 710,899