Long-Term Debt - Schedule of Debt (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Long-term debt	$ 7,885,783	$ 7,380,443
Long-term debt, fair value	606,956	248,856
Structured notes matures in 2018	1,016,300
Structured notes matures in 2019	777,700
Structured notes matures in 2022	232,500
Parent Company
Debt Instrument [Line Items]
Long-term debt	989,021	987,891
Subsidiaries
Debt Instrument [Line Items]
Long-term debt	6,896,762	6,392,552
Credit Facility | Foursight Capital
Debt Instrument [Line Items]
Long-term debt	$ 170,455	$ 97,138
5.50% Senior Notes due October 18, 2023
Debt Instrument [Line Items]
Interest rate	5.50%	5.50%
Principal	$ 750,000	$ 750,000
5.50% Senior Notes due October 18, 2023 | Parent Company
Debt Instrument [Line Items]
Long-term debt	$ 742,348	$ 741,264
6.625% Senior Notes due October 23, 2043
Debt Instrument [Line Items]
Interest rate	6.625%	6.625%
Principal	$ 250,000	$ 250,000
6.625% Senior Notes due October 23, 2043 | Parent Company
Debt Instrument [Line Items]
Long-term debt	$ 246,673	$ 246,627
5.125% Senior Notes, due April 13, 2018
Debt Instrument [Line Items]
Interest rate	5.125%	5.125%
Principal	$ 678,300	$ 800,000
5.125% Senior Notes, due April 13, 2018 | Subsidiaries
Debt Instrument [Line Items]
Long-term debt	$ 682,338	$ 817,813
8.5% Senior Notes, due July 15, 2019
Debt Instrument [Line Items]
Interest rate	8.50%	8.50%
Principal	$ 680,800	$ 700,000
8.5% Senior Notes, due July 15, 2019 | Subsidiaries
Debt Instrument [Line Items]
Long-term debt	$ 728,872	$ 778,367
2.375% Euro Senior Notes, due May 20, 2020
Debt Instrument [Line Items]
Interest rate	2.375%	2.375%
Principal	$ 594,725	$ 529,975
2.375% Euro Senior Notes, due May 20, 2020 | Subsidiaries
Debt Instrument [Line Items]
Long-term debt	$ 593,334	$ 528,250
6.875% Senior Notes, due April 15, 2021
Debt Instrument [Line Items]
Interest rate	6.875%	6.875%
Principal	$ 750,000	$ 750,000
6.875% Senior Notes, due April 15, 2021 | Subsidiaries
Debt Instrument [Line Items]
Long-term debt	$ 808,157	$ 823,797
2.25% Euro Medium Term Notes, due July 13, 2022
Debt Instrument [Line Items]
Interest rate	2.25%	2.25%
Principal	$ 4,758	$ 4,240
2.25% Euro Medium Term Notes, due July 13, 2022 | Subsidiaries
Debt Instrument [Line Items]
Long-term debt	$ 4,389	$ 3,848
5.125% Senior Notes, due January 20, 2023
Debt Instrument [Line Items]
Interest rate	5.125%	5.125%
Principal	$ 600,000	$ 600,000
5.125% Senior Notes, due January 20, 2023 | Subsidiaries
Debt Instrument [Line Items]
Long-term debt	$ 615,703	$ 618,355
4.85% Senior Notes, due January 15, 2027
Debt Instrument [Line Items]
Interest rate	4.85%	0.00%
Principal	$ 750,000	$ 0
4.85% Senior Notes, due January 15, 2027 | Subsidiaries
Debt Instrument [Line Items]
Long-term debt	736,357	$ 0
4.85% Senior Notes, due January 15, 2027 | Subsidiaries | Interest rate swaps
Debt Instrument [Line Items]
Increase (Decrease) of Long-term Debt	$ 8,100
6.45% Senior Debentures, due June 8, 2027
Debt Instrument [Line Items]
Interest rate	6.45%	6.45%
Principal	$ 350,000	$ 350,000
6.45% Senior Debentures, due June 8, 2027 | Subsidiaries
Debt Instrument [Line Items]
Long-term debt	$ 375,794	$ 377,806
3.875% Convertible Senior Debentures, due November 1, 2029
Debt Instrument [Line Items]
Interest rate	3.875%	3.875%	3.875%
Principal	$ 324,779	$ 345,000
3.875% Convertible Senior Debentures, due November 1, 2029 | Jefferies
Debt Instrument [Line Items]
Interest rate	3.875%
3.875% Convertible Senior Debentures, due November 1, 2029 | Subsidiaries
Debt Instrument [Line Items]
Long-term debt	$ 324,779	$ 346,163
6.25% Senior Debentures, due January 15, 2036
Debt Instrument [Line Items]
Interest rate	6.25%	6.25%
Principal	$ 500,000	$ 500,000
6.25% Senior Debentures, due January 15, 2036 | Subsidiaries
Debt Instrument [Line Items]
Long-term debt	$ 512,040	$ 512,396
6.50% Senior Notes, due January 20, 2043
Debt Instrument [Line Items]
Interest rate	6.50%	6.50%
Principal	$ 400,000	$ 400,000
6.50% Senior Notes, due January 20, 2043 | Subsidiaries
Debt Instrument [Line Items]
Long-term debt	420,990	421,333
Structured Notes | Jefferies
Debt Instrument [Line Items]
Long-term debt, fair value	607,000	248,900
Structured Notes | Subsidiaries
Debt Instrument [Line Items]
Long-term debt	614,091	255,203
Structured notes matures in 2018	7,100
Structured notes matures in 2019	6,000
Structured notes matures in 2022	25,000
Structured notes matures in 2024 and thereafter	576,000
Reducing Revolver Loan | National Beef
Debt Instrument [Line Items]
Long-term debt	$ 120,000	0
Interest rate	3.30%
Revolving Credit Facility | National Beef
Debt Instrument [Line Items]
Long-term debt	$ 76,809	0
Interest rate	3.30%
Term Loan | National Beef
Debt Instrument [Line Items]
Long-term debt	$ 0	273,811
Term Loan | 54 Madison
Debt Instrument [Line Items]
Long-term debt	0	406,028
Other | Subsidiaries
Debt Instrument [Line Items]
Long-term debt	$ 112,654	$ 132,244