Discontinued Operations (Summary of discontinued operations) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Aug. 31, 2019	Sep. 30, 2018	Aug. 31, 2019	Sep. 30, 2018
Expenses:
Income tax provision	$ 0	$ 0	$ 0	$ 47,045
Income from discontinued operations, net of income tax provision	$ 0	$ 0	$ 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				3,142,071
Expenses:
Compensation and benefits				17,414
Cost of sales				2,884,983
Interest expense				4,316
Depreciation and amortization				43,959
Selling, general and other expenses				14,291
Total expenses				2,964,963
Income from discontinued operations before income taxes				177,108
Income tax provision				47,045
Income from discontinued operations, net of income tax provision				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				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				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				$ 4,329