Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2015	Jul. 31, 2014	Jul. 31, 2015	Jul. 31, 2014	Jan. 31, 2015
Disclosure Income Taxes Additional Information [Abstract]
Income tax expense (benefit)	$ 4,071	$ (1,768)	$ 2,559	$ (1,942)
Effective tax rate	11.70%	(14.70%)	11.30%	(22.10%)
Period specific items benefit			$ (1,618)
Effective income tax rate forecast			16.00%
U.S. federal statutory rate			35.00%
Income taxes associated with uncertain income tax positions	$ 19,098		$ 19,098
Liability for uncertain tax positions, current	238		238
Income tax liability	$ 18,860		$ 18,860		$ 19,279