CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jul. 31, 2019	Apr. 30, 2019
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts	$ 21,732	$ 21,582
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	73,076,000	72,442,000
Common stock, shares outstanding	56,596,000	56,431,000