Accounting Policies and Basis of Presentation - Supplemental Cash Flow Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jul. 31, 2016	Jul. 31, 2015
Supplemental Cash Flow Information [Abstract]
Income taxes paid	$ 514	$ 1,109
Income tax refunds	(171)	(3,976)
Interest paid	6,086	4,683
Noncash investing and financing activities:
Exchange of 4.25% convertible notes for 8.0% convertible notes		55,500
Accrued capital additions	$ 2,772	$ 1,442