Fair Value Measurements (Estimated Fair Values Of Debt Instruments) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Level 1 [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	$ 0	$ 0
Financial Liabilities Fair Value Disclosure	5,881	1,975
Level 2 [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	6,914	444,502
Financial Liabilities Fair Value Disclosure	36,598	38,921
Fair Value, Inputs, Level 3 [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure		205
Financial Liabilities Fair Value Disclosure	3,629	2,759
Marketable securities | Level 2 [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure		424,148
Nymex Futures Contracts [Member]
Debt Instrument [Line Items]
Financial Liabilities Fair Value Disclosure		1,975
Nymex Futures Contracts [Member] | Level 1 [Member]
Debt Instrument [Line Items]
Financial Liabilities Fair Value Disclosure	5,881	1,975
Nymex Futures Contracts [Member] | Level 2 [Member]
Debt Instrument [Line Items]
Financial Liabilities Fair Value Disclosure	0	0
Commodity Contract [Member] | Level 1 [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure		0
Commodity Contract [Member] | Level 2 [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	5,556	14,358
Financial Liabilities Fair Value Disclosure	12,401	24,086
Commodity Contract [Member] | Fair Value, Inputs, Level 3 [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure		205
Financial Liabilities Fair Value Disclosure	3,629	2,759
Forward Contracts [Member] | Level 2 [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	1,358	5,905
Financial Liabilities Fair Value Disclosure	1,611	8,316
Interest Rate Swap [Member] | Level 2 [Member] | HEP [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure		91
Foreign Exchange Forward [Member] | Level 2 [Member]
Debt Instrument [Line Items]
Financial Liabilities Fair Value Disclosure		6,519
Reported Value Measurement [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	6,914	444,707
Financial Liabilities Fair Value Disclosure	46,108	43,655
Reported Value Measurement [Member] | Marketable securities
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure		424,148
Reported Value Measurement [Member] | Nymex Futures Contracts [Member]
Debt Instrument [Line Items]
Financial Liabilities Fair Value Disclosure	5,881
Reported Value Measurement [Member] | Commodity Contract [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	5,556	14,563
Financial Liabilities Fair Value Disclosure	16,030	26,845
Reported Value Measurement [Member] | Forward Contracts [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	1,358	5,905
Financial Liabilities Fair Value Disclosure	$ 1,611	8,316
Reported Value Measurement [Member] | Interest Rate Swap [Member] | HEP [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure		91
Reported Value Measurement [Member] | Foreign Exchange Forward [Member]
Debt Instrument [Line Items]
Financial Liabilities Fair Value Disclosure		$ 6,519