Fair Value Measurements (Assets and Liabilities Measured on Recurring Basis) (Details) - Fair Value, Recurring [Member] - USD ($) $ in Thousands		Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019
Assets and liabilities measured at fair value on a recurring basis
Commodity derivatives, net	[1]	$ 45,916	$ 61,365	$ 165,822
Provisionally price contracts	[2]	(57,036)	(186,651)	(39,279)
Convertible preferred securities	[3]	8,654	8,404	8,404
Other assets and liabilities	[4]	(30,820)	(4,038)	(5,466)
Total		(33,286)	(120,920)	129,481
Level 1
Assets and liabilities measured at fair value on a recurring basis
Commodity derivatives, net	[1]	22,162	45,682	103,350
Provisionally price contracts	[2]	(15,139)	(118,414)	(1,064)
Convertible preferred securities	[3]	0	0	0
Other assets and liabilities	[4]	4,102	9,469	5,284
Total		11,125	(63,263)	107,570
Level 2
Assets and liabilities measured at fair value on a recurring basis
Commodity derivatives, net	[1]	23,754	15,683	62,472
Provisionally price contracts	[2]	(41,897)	(68,237)	(38,215)
Convertible preferred securities	[3]	0	0	0
Other assets and liabilities	[4]	(34,922)	(13,507)	(10,750)
Total		(53,065)	(66,061)	13,507
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).