Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Fair Value of Financial Assets and Liabilities Measured on Recurring Basis (Parenthetical) (Detail)

v2.4.1.9
Fair Value Measurements - Fair Value of Financial Assets and Liabilities Measured on Recurring Basis (Parenthetical) (Detail) (Fair Value, Inputs, Level 3 [Member], USD $)
3 Months Ended
Apr. 30, 2015
Fair Value, Inputs, Level 3 [Member]
 
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Liability, fair value adjustment $ 0us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityPeriodIncreaseDecrease
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member