Earnings Per Share - Computation of EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Feb. 28, 2022	Feb. 28, 2021	Feb. 28, 2022	Feb. 28, 2021
Basic earnings per share:
Net income	$ 315,448	$ 258,384	$ 941,296	$ 843,246
Less: income allocated to participating securities	1,581	1,894	4,706	5,908
Income available to common shareholders	$ 313,867	$ 256,490	$ 936,590	$ 837,338
Basic weighted average common shares outstanding (in shares)	103,388	105,264	103,438	104,782
Basic earnings per share (in dollars per share)	$ 3.04	$ 2.44	$ 9.05	$ 7.99
Diluted earnings per share:
Net income	$ 315,448	$ 258,384	$ 941,296	$ 843,246
Less: income allocated to participating securities	1,581	1,894	4,706	5,908
Income available to common shareholders	$ 313,867	$ 256,490	$ 936,590	$ 837,338
Basic weighted average common shares outstanding (in shares)	103,388	105,264	103,438	104,782
Effect of dilutive securities - employee stock options (in shares)	2,253	2,732	2,458	2,914
Diluted weighted average common shares outstanding (in shares)	105,641	107,996	105,896	107,696
Diluted earnings per share (in dollars per share)	$ 2.97	$ 2.37	$ 8.84	$ 7.78