Fair Value Measurements (Estimated Fair Values Of Debt Instruments) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Level 1 [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	$ 662	$ 0
Financial Liabilities Fair Value Disclosure	0	1,975
Level 2 [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	9,373	444,502
Financial Liabilities Fair Value Disclosure	21,849	38,921
Fair Value, Inputs, Level 3 [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure		205
Financial Liabilities Fair Value Disclosure		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 Assets Fair Value Disclosure	662
Financial Liabilities Fair Value Disclosure		1,975
Nymex Futures Contracts [Member] | Level 1 [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	662
Financial Liabilities Fair Value Disclosure		1,975
Nymex Futures Contracts [Member] | Level 2 [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	0
Financial Liabilities Fair Value Disclosure		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	7,863	14,358
Financial Liabilities Fair Value Disclosure	20,631	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		2,759
Forward Contracts [Member] | Level 2 [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	1,447	5,905
Financial Liabilities Fair Value Disclosure	1,218	8,316
Interest Rate Swap [Member] | HEP [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	63
Interest Rate Swap [Member] | Level 2 [Member] | HEP [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	63	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	10,035	444,707
Financial Liabilities Fair Value Disclosure	21,849	43,655
Reported Value Measurement [Member] | Marketable securities
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure		424,148
Reported Value Measurement [Member] | Commodity Contract [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	7,863	14,563
Financial Liabilities Fair Value Disclosure	20,631	26,845
Reported Value Measurement [Member] | Forward Contracts [Member]
Debt Instrument [Line Items]
Financial Assets Fair Value Disclosure	1,447	5,905
Financial Liabilities Fair Value Disclosure	$ 1,218	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