Dividends and Treasury Stock Dividends paid (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
		Apr. 30, 2019	Apr. 30, 2018
Stockholders' Equity Note [Abstract]
Payments of Ordinary Dividends, Common Stock	[1]	$ 4,682	$ 4,658
Cash dividends paid per common share (in dollars per share)	[1]	$ 0.130	$ 0.130
Dividends Payable		$ 0	$ 0

[1] There were no declared and unpaid shareholder dividends at April 30, 2019 or 2018.