Investments (Details) - USD ($)	12 Months Ended
May 31, 2019	May 31, 2018	May 31, 2017
Investments [Abstract]
Investments	$ 192,346,000	$ 175,581,000
Cash surrender value of life insurance policies	170,500,000	154,000,000
Equity method investments	18,600,000	16,400,000
Cost method investments	3,200,000	5,200,000
Losses due to impairment	0	0	$ 0
Proceeds from sale of a cost method investment	73,342,000	0	0
Pre-tax gain on sale of cost method investment	$ 69,373,000	$ 0	$ 0

Carrying amount as of the balance sheet date of amounts which could be received based on the terms of the insurance contract upon surrendering life policies owned by the entity.

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Amount, after adjustment, of cost-method investment. Adjustments include, but are not limited to, dividends received in excess of earnings after date of investment that are considered a return of investment and other than temporary impairments.

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This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

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The net realized gain (loss) on investments sold during the period, not including gains (losses) on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity, which, for cash flow reporting, is a component of proceeds from investing activities.

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The amount by which the fair value of an investment is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

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Sum of the carrying amounts as of the balance sheet date of all investments.

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Amount of cash inflow from the sale of investments classified as other.

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