CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jul. 31, 2015	Apr. 30, 2015
Allowance for doubtful accounts	$ 10,344	$ 9,958
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	63,549,000	62,863,000
Common stock, shares outstanding	51,195,000	50,573,000