Fair Value Measurements (Estimated Fair Values Of Debt Instruments) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Level 1 [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	$ 1,530	$ 0
Financial Liabilities Fair Value Disclosure	0	2,578
Level 2 [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	2,891	17,588
Financial Liabilities Fair Value Disclosure	10,491	11,637
Fair Value, Inputs, Level 3
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	0	0
Financial Liabilities Fair Value Disclosure	0	0
Reported Value Measurement [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	4,421	17,588
Financial Liabilities Fair Value Disclosure	10,491	14,215
NYMEX futures contracts | Level 1 [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	1,530
Financial Liabilities Fair Value Disclosure		2,578
NYMEX futures contracts | Level 2 [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	0
Financial Liabilities Fair Value Disclosure		0
NYMEX futures contracts | Fair Value, Inputs, Level 3
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	0
Financial Liabilities Fair Value Disclosure		0
NYMEX futures contracts | Reported Value Measurement [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	1,530
Financial Liabilities Fair Value Disclosure		2,578
Commodity price swaps | Level 1 [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	0	0
Financial Liabilities Fair Value Disclosure	0	0
Commodity price swaps | Level 2 [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	2,820	13,455
Financial Liabilities Fair Value Disclosure	134	1,230
Commodity price swaps | Fair Value, Inputs, Level 3
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	0	0
Financial Liabilities Fair Value Disclosure	0	0
Commodity price swaps | Reported Value Measurement [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	2,820	13,455
Financial Liabilities Fair Value Disclosure	134	1,230
Foreign currency forward contracts | Level 1 [Member]
Debt Instrument [Line Items]
Financial Liabilities Fair Value Disclosure	0	0
Foreign currency forward contracts | Level 2 [Member]
Debt Instrument [Line Items]
Financial Liabilities Fair Value Disclosure	3,589	6,722
Foreign currency forward contracts | Fair Value, Inputs, Level 3
Debt Instrument [Line Items]
Financial Liabilities Fair Value Disclosure	0	0
Foreign currency forward contracts | Reported Value Measurement [Member]
Debt Instrument [Line Items]
Financial Liabilities Fair Value Disclosure	3,589	6,722
Commodity forward contracts | Level 1 [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	0	0
Financial Liabilities Fair Value Disclosure	0	0
Commodity forward contracts | Level 2 [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	71	4,133
Financial Liabilities Fair Value Disclosure	58	3,685
Commodity forward contracts | Fair Value, Inputs, Level 3
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	0	0
Financial Liabilities Fair Value Disclosure	0	0
Commodity forward contracts | Reported Value Measurement [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	71	4,133
Financial Liabilities Fair Value Disclosure	58	$ 3,685
RINs credit obligations | Level 1 [Member]
Debt Instrument [Line Items]
Financial Liabilities Fair Value Disclosure	0
RINs credit obligations | Level 2 [Member]
Debt Instrument [Line Items]
Financial Liabilities Fair Value Disclosure	6,710
RINs credit obligations | Fair Value, Inputs, Level 3
Debt Instrument [Line Items]
Financial Liabilities Fair Value Disclosure	0
RINs credit obligations | Reported Value Measurement [Member]
Debt Instrument [Line Items]
Financial Liabilities Fair Value Disclosure	$ 6,710