Stock-Based Compensation - Stock Options Granted and Outstanding (Details) - $ / shares	12 Months Ended
	May 31, 2021	May 31, 2020	May 31, 2019	May 31, 2018
Shares
Outstanding, beginning of period (shares)	7,105,399	8,208,934	8,930,186
Granted (shares)	747,550	575,813	1,013,005
Canceled (shares)	(1,452)	(5,432)	(3,045)
Forfeited (shares)	(91,722)	(312,391)	(397,304)
Exercised (shares)	(1,704,251)	(1,361,525)	(1,333,908)
Outstanding, end of period (shares)	6,055,524	7,105,399	8,208,934
Options exercisable (shares)	1,548,867	1,913,374	1,919,976	2,006,922
Weighted Average Exercise Price
Outstanding, beginning of period, Weighted Average Exercise Price (dollars per share)	$ 145.54	$ 123.80	$ 96.71
Granted, Weighted Average Exercise Price (dollars per share)	348.24	250.50	219.37
Canceled, Weighted Average Exercise Price (dollars per share)	59.51	72.17	58.03
Forfeited, Weighed Average Exercise Price (dollars per share)	193.94	185.08	155.39
Exercised, Weighted Average Exercise Price (dollars per share)	83.31	70.03	54.14
Outstanding, end of period, Weighted Average Exercise Price (dollars per share)	$ 191.11	$ 145.54	$ 123.80