Dividends and Treasury Stock (Details) - USD ($)	3 Months Ended		9 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015	Mar. 21, 2016
Stockholders' Equity Note [Abstract]
Dividends paid	$ 4,690,000	$ 4,764,000	$ 14,078,000	$ 14,598,000
Cash dividends paid per common share (in dollars per share)	$ 0.13	$ 0.13000	$ 0.39	$ 0.39
Stock Repurchase Program, Authorized Amount	$ 50,000,000	$ 40,000,000	$ 50,000,000	$ 40,000,000
Stock repurchase program, additional amount authorized					$ 10,000,000
Payments for Repurchase of Common Stock	0	$ 18,512,800	7,702,000	$ 29,338,000
Unpaid repurchases of common stock	0		0
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 12,959,000		$ 12,959,000