Net Income per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015
Earnings Per Share [Abstract]
Net income	$ 23,998	$ 6,003	$ 27,745	$ 10,276
Weighted average shares outstanding (shares)	15,128	14,971	15,047	14,895
Net effect of dilutive share-based on the treasury stock method using average market price (shares)	165	353	139	332
Totals (shares)	15,293	15,324	15,186	15,227
Net income per share - basic (usd per share)	$ 1.59	$ 0.40	$ 1.84	$ 0.69
Net income per share - diluted (usd per share)	$ 1.57	$ 0.39	$ 1.83	$ 0.67