Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
May 31, 2018	May 31, 2017	May 31, 2016
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 3,046,440	$ 2,839,878
Less: accumulated depreciation	1,663,710	1,516,377
Property, plant and equipment, net	1,382,730	1,323,501
Capitalized interest	1,000	2,100	$ 1,100
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	177,281	173,166
Buildings and improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	644,322	624,615
Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	2,070,009	1,930,018
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	34,891	32,679
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	119,937	79,400
Internal Use Software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 253,800	229,000
Property and equipment, useful lives	10 years
Less: accumulated depreciation	$ 88,800	$ 78,300

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount of interest costs capitalized disclosed as an adjusting item to interest costs incurred.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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