Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	May 31, 2020	May 31, 2019
Statement of Financial Position [Abstract]
Allowance on accounts receivable	$ 62,167	$ 37,809
Preferred stock, shares authorized (in shares)	100,000	100,000
Preferred stock, shares outstanding ( in shares)	0	0
Common stock, shares authorized (in shares)	425,000,000	425,000,000
Common stock, shares issued (in shares)	186,793,207	184,790,626
Common stock, shares outstanding (in shares)	103,415,368	103,284,401
Treasury stock, shares (in shares)	83,377,839	81,506,225