Dividends and Treasury Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Apr. 30, 2016	Apr. 30, 2015
Stockholders' Equity Note [Abstract]
Dividends paid	$ 4,701	$ 4,940
Cash dividends paid per common share (in dollars per share)	$ 0.13	$ 0.13000
Stock Repurchase Program, Authorized Amount	$ 50,000	$ 40,000
Stock Repurchase Program, Additional Authorized Amount	$ 10,000
Shares repurchased, Treasury Stock	382,065	149,359
Stock Repurchased and Retired During Period, Value	$ 5,702	$ 3,044
Payments for Repurchase of Common Stock	5,702	2,563
Unpaid repurchases of common stock	0	$ 481
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 14,959