Earnings Per Share - Computation of EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Nov. 30, 2020	Nov. 30, 2019	Nov. 30, 2020	Nov. 30, 2019
Basic earnings per share:
Income from continuing operations	$ 284,857	$ 246,443	$ 584,862	$ 497,255
Less: income from continuing operations allocated to participating securities	2,015	2,425	4,153	4,904
Income from continuing operations available to common shareholders	$ 282,842	$ 244,018	$ 580,709	$ 492,351
Basic weighted average common shares outstanding (in shares)	104,999	103,959	104,546	103,638
Basic earnings per share from continuing operations (in dollars per share)	$ 2.69	$ 2.35	$ 5.55	$ 4.75
Diluted earnings per share:
Income from continuing operations	$ 284,857	$ 246,443	$ 584,862	$ 497,255
Less: income from continuing operations allocated to participating securities	2,015	2,425	4,153	4,904
Income from continuing operations available to common shareholders	$ 282,842	$ 244,018	$ 580,709	$ 492,351
Basic weighted average common shares outstanding (in shares)	104,999	103,959	104,546	103,638
Effect of dilutive securities - employee stock options (in shares)	2,982	3,376	3,010	3,476
Diluted weighted average common shares outstanding (in shares)	107,981	107,335	107,556	107,114
Diluted earnings per share from continuing operations (in dollars per share)	$ 2.62	$ 2.27	$ 5.40	$ 4.60