Summary of Level 3 Activity (Detail) $ in Thousands	6 Months Ended
	Jul. 31, 2015 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 4,563
Payments	(1,525)
Adjustment	(97)
Interest accretion	67
Balance at ending of period	$ 3,008