CONDENSED CONSOLIDATED BALANCE SHEETS (Parentheticals) - USD ($) shares in Thousands, $ in Thousands	Apr. 30, 2016	Jan. 31, 2016	Apr. 30, 2015
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts and sales discounts on accounts receivable (in dollars)	$ 60,682	$ 74,261	$ 48,574
Preferred stock, shares authorized	1,000	1,000	1,000
Preferred stock, shares issued	0	0	0
Preferred stock, shares outstanding	0	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Common stock, shares authorized	120,000	120,000	120,000
Common stock, shares issued	46,231	46,212	45,964
Treasury stock, shares	667	667	984