Dividends and Treasury Stock Dividends paid (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018
Stockholders' Equity Note [Abstract]
Payments of Ordinary Dividends, Common Stock	$ 4,648	$ 4,674	$ 14,001	$ 14,000
Cash dividends paid per common share (in dollars per share)	$ 0.130	$ 0.130	$ 0.390	$ 0.390
Dividends Payable	$ 0	$ 0	$ 0	$ 0