Income Taxes - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Feb. 28, 2019	May 31, 2019	May 31, 2018	May 31, 2017
Income Tax Disclosure [Abstract]
Income taxes paid		$ 173,200	$ 175,300	$ 269,600
Unrecognized tax benefits that would impact effective tax rates if recognized		37,300	26,900
Unrecognized tax benefits, interest and penalties accrued		2,800	1,800
Tax Act, deferred tax remeasurement, provisional income tax benefit			175,600
Tax Act, provisional transition income tax expense			9,800
Measurement period adjustment, deferred tax remeasurement, income tax expense	$ 400
Measurement period adjustment, transition tax, income tax expense	$ 200
Non-U.S. withholding taxes related to certain non-U.S. earnings subject to repatriation		690	$ 4,363	$ 0
Unrecognized tax liability associated with operations permanently reinvested		$ 5,400