Discontinued Operations (Summary of discontinued operations) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	May 31, 2019	Jun. 30, 2018	May 31, 2019	Jun. 30, 2018
Expenses:
Income tax provision	$ 0	$ 31,111	$ 0	$ 47,045
Income from discontinued operations, net of income tax provision	$ 0	77,106	$ 0	130,063
National Beef | Discontinued operations, disposed of by sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues		1,356,713		3,142,071
Expenses:
Compensation and benefits		7,207		17,414
Cost of sales		1,214,207		2,884,983
Interest expense		2,207		4,316
Depreciation and amortization		18,440		43,959
Selling, general and other expenses		6,435		14,291
Total expenses		1,248,496		2,964,963
Income from discontinued operations before income taxes		108,217		177,108
Income tax provision		31,111		47,045
Income from discontinued operations, net of income tax provision		77,106		130,063
National Beef | Discontinued operations, disposed of by sale | Beef processing services
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues		1,355,691		3,137,611
National Beef | Discontinued operations, disposed of by sale | Interest income
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues		63		131
National Beef | Discontinued operations, disposed of by sale | Other
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues		$ 959		$ 4,329