Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Apr. 30, 2020	Apr. 30, 2019
Earnings Per Share [Abstract]
Net income	$ 48,065	$ 55,400
Weighted average common shares - basic	35,688,000	37,011,000
Equity based awards	314,000	236,000
Weighted average common shares - diluted	36,002,000	37,247,000
Basic Earnings Per Share	$ 1.35	$ 1.50
Diluted Earnings Per Share	$ 1.34	$ 1.49
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	322