CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jan. 31, 2021	Apr. 30, 2020	Jan. 31, 2020
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 34,493	$ 64,648	$ 45,254
Accumulated depreciation and amortization	$ 851,731	$ 796,192	$ 803,272
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)	218,719,439	228,206,684	228,206,684
Treasury stock, shares (in shares)	35,225,825	35,731,376	35,732,666