Dividends and Treasury Stock (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2020	Jul. 31, 2019	Jan. 31, 2015
Stockholders' Equity Note [Abstract]
Stock Repurchase Program, Authorized Amount	$ 75,000		$ 75,000		$ 40,000
Shares repurchased, Treasury Stock	0	102,477	0	163,177
Payments for Repurchase of Common Stock		$ 3,500	$ 0	$ 5,781
Unpaid repurchases of common stock	$ 0	$ 0	0	$ 0
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 17,179		$ 17,179