Warranties (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2015	Jul. 31, 2014	Jul. 31, 2015	Jul. 31, 2014
Product Warranty Accrual [Roll Forward]
Beginning balance	$ 2,285	$ 2,654	$ 3,120	$ 2,525
Accrual for warranties	389	648	748	1,389
Settlements made	(922)	(685)	(2,116)	(1,297)
Ending balance	$ 1,752	$ 2,617	$ 1,752	$ 2,617