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Accounting for Leases - Additional Information (Detail)
 12 Months Ended
Jan. 31, 2016
Accounting For Leases [Line Items]  
Maximum optional renewal period under operating leases, years 20 years
Minimum  
Accounting For Leases [Line Items]  
Operating lease term, years 3 years
Maximum  
Accounting For Leases [Line Items]  
Operating lease term, years 22 years