Derivative Financial Instruments (Schedule of Derivatives Instruments Statements of Financial Position) (Details) - Commodity contract - Futures - Cost of goods sold - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Designated as hedging instrument
Amount of gain (loss) recognized in income on derivatives	$ 7,786	$ 838
Amount of gain (loss) recognized in income on related hedged items	(2,396)	500
Designated as hedging instrument | Firm commitments
Amount of gain (loss) recognized in income on related hedged items	(1,898)	1,739
Designated as hedging instrument | Inventory
Amount of gain (loss) recognized in income on related hedged items	(498)	(1,239)
Not designated as hedging instrument
Amount of gain (loss) recognized in income on derivatives	$ (30,195)	$ 10,939