Data Breach - Insurance Coverage (Details) - Data Breach - USD ($)	9 Months Ended	24 Months Ended
	Oct. 31, 2015	Oct. 31, 2015
Loss Contingencies [Line Items]
Network-security insurance coverage	$ 100,000,000
Deductible amount	10,000,000
Sublimit for settlements	$ 50,000,000
Amount from network-security insurance carriers		$ 35,000,000
Amount accrued		$ 90,000,000