Warranties (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2014	Jul. 31, 2013
Product Warranty Accrual [Roll Forward]
Beginning balance	$ 2,654	$ 1,990	$ 2,525	$ 1,888
Accrual for warranties	648	868	1,389	1,732
Settlements made (in cash or in kind)	(685)	(811)	(1,297)	(1,573)
Ending balance	$ 2,617	$ 2,047	$ 2,617	$ 2,047