Income Taxes - Components of Income Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
May 31, 2018	May 31, 2017	May 31, 2016
Income before income taxes for continuing operations consists of the following components:
U.S. operations	$ 798,215	$ 673,055	$ 685,167
Foreign operations	42,786	14,349	20,148
Income before income taxes from continuing operations	$ 841,001	$ 687,404	$ 705,315

The portion of earnings or loss from continuing operations before income taxes that is attributable to domestic operations.

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Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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The portion of earnings or loss from continuing operations before income taxes that is attributable to foreign operations, which is defined as Income or Loss generated from operations located outside the entity's country of domicile.

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