Consolidated Condensed Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Feb. 28, 2018	Nov. 30, 2017	Aug. 31, 2017	Feb. 28, 2017	Nov. 30, 2016	Aug. 31, 2016	Feb. 28, 2018	Feb. 28, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 302,095			$ 118,005			$ 656,415	$ 396,473
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	2,374			2,400			26,184	(5,135)
Change in fair value of cash flow hedges	0			2,560			0	16,913
Amortization of interest rate lock agreements	(294)			385			(638)	1,155
Other comprehensive income	2,080	$ (11,566)	$ 35,032	5,345	$ 19,126	$ (11,538)	25,546	12,933
Comprehensive income	$ 304,175			$ 123,350			$ 681,961	$ 409,406

Other Comprehensive Income (Loss), Amortization of Interest Rate Lock Agreements, Net of Tax

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Amount after tax and reclassification adjustments, of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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