Fair Value Measurements (Assets and Liabilities Measured on Recurring Basis) (Details) - Fair Value, Recurring [Member] - USD ($) $ in Thousands		Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019
Assets and liabilities measured at fair value on a recurring basis
Commodity derivatives, net	[1]	$ 63,516	$ 61,365	$ 52,887
Provisionally price contracts	[2]	(27,731)	(186,651)	(103,292)
Convertible preferred securities	[3]	8,654	8,404	8,404
Other assets and liabilities	[4]	(27,212)	(4,038)	(12,288)
Total		17,227	(120,920)	(54,289)
Level 1
Assets and liabilities measured at fair value on a recurring basis
Commodity derivatives, net	[1]	11,951	45,682	34,196
Provisionally price contracts	[2]	(5,190)	(118,414)	(79,757)
Convertible preferred securities	[3]	0	0	0
Other assets and liabilities	[4]	4,998	9,469	5,603
Total		11,759	(63,263)	(39,958)
Level 2
Assets and liabilities measured at fair value on a recurring basis
Commodity derivatives, net	[1]	51,565	15,683	18,691
Provisionally price contracts	[2]	(22,541)	(68,237)	(23,535)
Convertible preferred securities	[3]	0	0	0
Other assets and liabilities	[4]	(32,210)	(13,507)	(17,891)
Total		(3,186)	(66,061)	(22,735)
Level 3
Assets and liabilities measured at fair value on a recurring basis
Commodity derivatives, net	[1]	0	0	0
Provisionally price contracts	[2]	0	0	0
Convertible preferred securities	[3]	8,654	8,404	8,404
Other assets and liabilities	[4]	0	0	0
Total		$ 8,654	$ 8,404	$ 8,404

[1] Includes associated cash posted/received as collateral

[2] Included in "Provisionally priced contracts" are those instruments based only on underlying futures values (Level 1) and delayed price contracts (Level 2)

[3] Recorded in “Other assets, net” on the Company’s Consolidated Balance Sheets related to certain available for sale securities.

[4] Included in other assets and liabilities are assets held by the Company to fund deferred compensation plans, ethanol risk management contracts, and foreign exchange derivative contracts (Level 1) and interest rate derivatives (Level 2).