Earnings per Share - Summary of Buyback Activity by Program (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
May 31, 2020	May 31, 2019	May 31, 2018
Equity, Class of Treasury Stock [Line Items]
Purchase Price	$ 464,518	$ 1,016,300	$ 127,319
Share Repurchase Programs
Equity, Class of Treasury Stock [Line Items]
Shares	1,607	4,803	518
Avg. Price per Share (in dollars per share)	$ 246.19	$ 198.53	$ 173.51
Purchase Price	$ 395,681	$ 953,445	$ 89,997
Buyback Program, August 2016
Equity, Class of Treasury Stock [Line Items]
Shares	0	2,130	518
Avg. Price per Share (in dollars per share)	$ 0	$ 192.55	$ 173.51
Purchase Price	$ 0	$ 410,003	$ 89,997
Buyback Program, October 2018
Equity, Class of Treasury Stock [Line Items]
Shares	1,607	2,673	0
Avg. Price per Share (in dollars per share)	$ 246.19	$ 203.30	$ 0
Purchase Price	$ 395,681	$ 543,442	$ 0
Buyback Program, October 2019
Equity, Class of Treasury Stock [Line Items]
Shares	0	0	0
Avg. Price per Share (in dollars per share)	$ 0	$ 0	$ 0
Purchase Price	$ 0	$ 0	$ 0

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Total cost of shares repurchased divided by the total number of shares repurchased.

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