Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2014	Jul. 31, 2013	Jan. 31, 2014
Income Tax Disclosure [Abstract]
Prepaid income taxes	$ 1,488,000		$ 1,488,000		$ 2,177,000
Prepaid foreign taxes	1,400,000		1,400,000		600,000
Prepaid domestic federal and state taxes	$ 100,000		$ 100,000		$ 1,600,000
Effective tax rate without impact	16.80%	28.30%	52.60%	19.30%
Federal statutory rate			34.00%