CONDENSED CONSOLIDATED BALANCE SHEETS (Parentheticals) - USD ($) $ in Millions	Apr. 30, 2020	Jan. 31, 2020	Apr. 30, 2019
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts	$ 10.4	$ 0.7	$ 0.9
Preferred stock, shares authorized	1,000,000	1,000,000	1,000,000
Preferred stock, shares issued	0	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Common stock, shares authorized	120,000,000	120,000,000	120,000,000
Common stock, shares issued	48,052,000	49,396,000	49,393,000
Treasury stock, shares	1,344,000	1,386,000	470,000