Fair Value Measurements (Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017
Assets and liabilities measured at fair value on a recurring basis
Commodity derivatives, net	[1]	$ 18,365	$ 536
Provisionally priced contracts	[2]	(134,741)	(165,284)
Convertible preferred securities	[3]	7,154	7,388
Other assets and liabilities	[4]	4,833	8,461
Total		(104,389)	(148,899)
Level 1
Assets and liabilities measured at fair value on a recurring basis
Commodity derivatives, net	[1]	37,229	18,603
Provisionally priced contracts	[2]	(76,175)	(98,190)
Convertible preferred securities	[3]	0	0
Other assets and liabilities	[4]	5,186	9,705
Total		(33,760)	(69,882)
Level 2
Assets and liabilities measured at fair value on a recurring basis
Commodity derivatives, net	[1]	(18,864)	(18,067)
Provisionally priced contracts	[2]	(58,566)	(67,094)
Convertible preferred securities	[3]	0	0
Other assets and liabilities	[4]	(353)	(1,244)
Total		(77,783)	(86,405)
Level 3
Assets and liabilities measured at fair value on a recurring basis
Commodity derivatives, net	[1]	0	0
Provisionally priced contracts	[2]	0	0
Convertible preferred securities	[3]	7,154	7,388
Other assets and liabilities	[4]	0	0
Total		$ 7,154	$ 7,388

[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] 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).

[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