Basis of Presentation and Significant Accounting Policies (Schedule of Impact of Applying New Revenue Recognition Standard) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenues:
Beef processing services	$ 1,781,920	$ 1,559,023
Commissions and other fees	147,902	145,822
Principal transactions	145,663	416,403
Investment banking	439,991	408,021
Interest income	275,290	223,630
Other	155,703	327,470
Total revenues	2,946,469	3,080,369
Interest expense	23,607	27,384
Net revenues	2,680,793	2,867,982
Expenses:
Cost of sales	1,752,711	1,533,094
Compensation and benefits	499,866	503,327
Floor brokerage and clearing fees	42,176	45,858
Depreciation and amortization	53,679	49,510
Selling, general and other expenses	234,200	182,138
Total expenses	2,606,239	2,341,311
Income before income taxes and income (loss) related to associated companies	74,554	526,671
Investment Banking And Capital Markets Segment
Revenues:
Interest expense	265,676	$ 212,387
Impact of Adoption of Revenue Recognition Standard | Accounting Standards Update 2014-09
Revenues:
Beef processing services	0
Commissions and other fees	0
Principal transactions	0
Investment banking	32,485
Interest income	0
Other	0
Total revenues	32,485
Interest expense	0
Net revenues	32,485
Expenses:
Cost of sales	0
Compensation and benefits	0
Floor brokerage and clearing fees	0
Depreciation and amortization	0
Selling, general and other expenses	32,485
Total expenses	32,485
Income before income taxes and income (loss) related to associated companies	0
Impact of Adoption of Revenue Recognition Standard | Accounting Standards Update 2014-09 | Investment Banking And Capital Markets Segment
Revenues:
Interest expense	0
Financial Results Prior to Adoption of Revenue Recognition Standard | Accounting Standards Update 2014-09
Revenues:
Beef processing services	1,781,920
Commissions and other fees	147,902
Principal transactions	145,663
Investment banking	407,506
Interest income	275,290
Other	155,703
Total revenues	2,913,984
Interest expense	23,607
Net revenues	2,648,308
Expenses:
Cost of sales	1,752,711
Compensation and benefits	499,866
Floor brokerage and clearing fees	42,176
Depreciation and amortization	53,679
Selling, general and other expenses	201,715
Total expenses	2,573,754
Income before income taxes and income (loss) related to associated companies	74,554
Financial Results Prior to Adoption of Revenue Recognition Standard | Accounting Standards Update 2014-09 | Investment Banking And Capital Markets Segment
Revenues:
Interest expense	$ 265,676