Holly Energy Partners (Narrative) (Details) $ / shares in Units, $ in Thousands		3 Months Ended					6 Months Ended	9 Months Ended	12 Months Ended			20 Months Ended
	Feb. 01, 2017 USD ($) $ / shares	Mar. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) shares	Sep. 30, 2017 USD ($)	Mar. 31, 2017 USD ($) mi	Dec. 31, 2016 USD ($) $ / shares shares	Jun. 30, 2017 USD ($)	Sep. 30, 2017 mi bbl	Dec. 31, 2017 USD ($) Customers mi shares bbl	Dec. 31, 2016 USD ($) $ / shares	Dec. 31, 2015 USD ($)	Dec. 31, 2017 USD ($) shares	Feb. 22, 2016
Schedule of Equity Method Investments [Line Items]
Percentage of general partner interest									50.00%
Percent contribution to subsidiary revenue									83.00%
Concentration risk, precentage of total revenues									10.00%
Deferred Credits and Other Liabilities, Noncurrent					$ 38,900
Repayment of term loan				$ 39,500	39,500				$ 0	$ 350,000	$ 0
Loss on early extinguishment of debt									(12,225)	$ (8,718)	(1,370)
General Partners' Contributed Capital							$ 1,100
Partners' Capital Account, Units, Sold in Private Placement | shares			37,250,000			3,420,000
Limited Partners' Cumulative Cash Distributions			$ 2,500						2,500			$ 2,500
Proceeds from Issuance of Private Placement						$ 103,000
Partners' Capital Account, Contributions						$ 2,100
Shares Issued, Price Per Share | $ / shares	$ 28.12					$ 30.18				$ 30.18
Net proceeds from common unit offerings - HEP							52,100		$ 52,110	$ 125,870	0
Limited Partners' Capital Account, Units Issued | shares			1,538,452						1,538,452			1,538,452
Common Unit Issuance Program							$ 200,000
Acquisition, Cash Consideration Paid	$ 862,100		$ 362,000						$ 250,000
Business Combination, Step Acquisition, Equity Interest in Acquiree, Fair Value			$ 112,000
Remeasurement gain on pipeline interest acquisition									$ 36,254
Stock Issued During Period, Shares, Period Increase (Decrease) | shares												2,241,907
Proceeds from Issuance of Common Stock												$ 77,100
UNEV Pipeline [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage			75.00%						75.00%			75.00%
Frontier Pipeline [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage			50.00%						50.00%			50.00%
Length of pipeline | mi									289
Production barrel capacity per day | bbl									72,000
HEP
Schedule of Equity Method Investments [Line Items]
Percentage of ownership in variable interest entity									59.00%
Percentage of general partner interest									2.00%
Number of significant customers | Customers									2
Payments to Acquire Other Productive Assets			$ 278,000
Equity Method Investment, Ownership Percentage			75.00%	50.00%				50.00%	75.00%			75.00%
Payments to Acquire Property, Plant, and Equipment									$ 62,000
Purchase Obligation Minimum Annualized Payment									15,100
Purchase of pipeline interests - HEP									(245,446)	$ (42,627)	$ (55,032)
Length of pipeline | mi								87
Pipeline Throughput Capacity | bbl								80,000
Extinguishment of Debt, Amount					30,800
Loss on early extinguishment of debt					$ 8,700
Long-term Purchase Commitment, Amount			$ 56,700						$ 324,500
Osage Pipeline [Member] [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage													50.00%
Length of pipeline | mi					135
Subsequent Event [Member]
Schedule of Equity Method Investments [Line Items]
Partners' Capital Account, Units, Sold in Private Placement | shares		3,700,000
Proceeds from Issuance of Private Placement		$ 110,000
Shares Issued, Price Per Share | $ / shares		$ 29.73
Subsequent Event [Member] | HEP
Schedule of Equity Method Investments [Line Items]
Percentage of general partner interest		57.00%