Earnings Per Share - Computation of EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Aug. 31, 2019	Aug. 31, 2018
Basic Earnings per Share from Continuing Operations
Income from continuing operations	$ 250,812	$ 212,547
Less: income from continuing operations allocated to participating securities	2,016	2,945
Income from continuing operations available to common shareholders	$ 248,796	$ 209,602
Basic weighted average common shares outstanding (in shares)	103,543	106,835
Basic earnings per share from continuing operations (in dollars per share)	$ 2.40	$ 1.96
Diluted Earnings per Share from Continuing Operations
Income from continuing operations	$ 250,812	$ 212,547
Less: income from continuing operations allocated to participating securities	2,016	2,945
Income from continuing operations available to common shareholders	$ 248,796	$ 209,602
Basic weighted average common shares outstanding (in shares)	103,543	106,835
Effect of dilutive securities - employee stock options (in shares)	3,540	3,813
Diluted weighted average common shares outstanding (in shares)	107,083	110,648
Diluted earnings per share from continuing operations (in dollars per share)	$ 2.32	$ 1.89