Dividends and Treasury Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2015	Oct. 31, 2014	Oct. 31, 2015	Oct. 31, 2014
Stockholders' Equity Note [Abstract]
Dividends paid	$ 4,764	$ 4,745	$ 14,598	$ 13,492
Cash dividends paid per common share (in dollars per share)	$ 0.13	$ 0.13	$ 0.39	$ 0.37
Stock Repurchase Program, Authorized Amount	$ 40,000		$ 40,000
Shares repurchased, Treasury Stock	1,052,587		1,602,545
Payments for Repurchase of Common Stock	$ 18,513		$ 29,338	$ 0
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 10,662		$ 10,662