Stock-Based Compensation (Details) (USD $)	12 Months Ended
	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2013
Schedule of transactions for stock options under Plan
Outstanding Option Beginning Balance	599,406	561,489	694,982
Options granted	116,880	106,440	258,600
Options exercised	(86,066)	(52,023)	(392,093)
Options cancelled	(14,000)	(16,500)
Outstanding Option Ending Balance	616,220	599,406	561,489
Weighted Average Exercise Price, Beginning Balance	$ 26.24	$ 24.67	$ 19.55
Options granted, Weighted Average Exercise Price	$ 41.71	$ 30.34	$ 26.59
Options exercised, Weighted Average Exercise Price	$ 19.75	$ 17.54	$ 16.88
Options cancelled, Weighted Average Exercise Price	$ 26.59	$ 26.59
Weighted Average Exercise Price, Ending Balance	$ 30.08	$ 26.24	$ 24.67