Income Taxes - Summary of Reported Income Tax (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 31, 2013	Oct. 31, 2012	Oct. 31, 2013	Oct. 31, 2012
Income Tax Disclosure [Abstract]
Income tax expense	$ 926	$ 1,005	$ 2,066	$ 1,878