Assets and liabilities measured at fair value (Details) $ in Thousands	Jul. 29, 2016 USD ($)
Reported amount | Current portion of long-term debt obligations
Liabilities:
Long-term obligations	$ 501,548
Reported amount | Long-term obligations
Liabilities:
Long-term obligations	2,556,464
Reported amount | Accrued expenses and other current liabilities
Liabilities:
Deferred compensation	5,605
Reported amount | Noncurrent Other liabilities
Liabilities:
Deferred compensation	16,774
Fair value measurements on recurring basis | Balance at the end of the period
Liabilities:
Long-term obligations	3,192,185
Deferred compensation	22,379
Fair value measurements on recurring basis | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1)
Liabilities:
Long-term obligations	2,417,167
Deferred compensation	22,379
Fair value measurements on recurring basis | Significant Other Observable Inputs (Level 2)
Liabilities:
Long-term obligations	$ 775,018