Assets and liabilities measured at fair value (Details) (USD $) In Thousands, unless otherwise specified	May 02, 2014	Jan. 31, 2014
Reported amount | Current portion of long-term debt obligations
Liabilities:
Long-term obligations	$ 100,989
Reported amount | Long-term obligations
Liabilities:
Long-term obligations	3,006,404
Reported amount | Accrued expenses and other current liabilities
Liabilities:
Deferred compensation	1,794
Reported amount | Noncurrent Other liabilities
Liabilities:
Deferred compensation	20,804
Noncurrent Other liabilities
Liabilities:
Derivative financial instruments	3,773	4,109
Fair value measurements on recurring basis | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1)
Assets:
Trading securities	376
Liabilities:
Long-term obligations	3,065,185
Deferred compensation	22,598
Fair value measurements on recurring basis | Significant Other Observable Inputs (Level 2)
Liabilities:
Long-term obligations	19,902
Derivative financial instruments	3,773
Fair value measurements on recurring basis | Balance at the end of the period
Liabilities:
Long-term obligations	3,085,087
Deferred compensation	22,598
Fair value measurements on recurring basis | Balance at the end of the period | Prepaid expenses and other current assets
Assets:
Trading securities	376
Fair value measurements on recurring basis | Balance at the end of the period | Noncurrent Other liabilities
Liabilities:
Derivative financial instruments	$ 3,773