CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jan. 31, 2020	Apr. 30, 2019	Jan. 31, 2019
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 45,254	$ 67,228	$ 44,033
Accumulated depreciation and amortization	$ 803,272	$ 745,761	$ 800,834
Common stock, stated value per share (in usd per share)	$ 0.01	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	800,000,000	800,000,000	800,000,000
Common stock, shares issued (in shares)	228,206,684	238,336,760	241,501,278
Treasury stock, shares (in shares)	35,732,666	36,377,441	36,460,305