Acquisitions - Washington Acquisition (Details) barrel / d in Thousands, shares in Millions, bbl in Millions		1 Months Ended	3 Months Ended			6 Months Ended
	Jan. 11, 2019 USD ($) mbpd shares bbl	Jan. 31, 2019 USD ($)	Jun. 30, 2019 USD ($) barrel / d	Mar. 31, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) barrel / d	Jun. 30, 2018 USD ($)	Jan. 09, 2019 USD ($)
Business Acquisition [Line Items]
Oil and gas refinery capacity | barrel / d			200			200
Issuance of common stock for business combination				$ 36,980,000		$ 37,000,000
Acquisition and integration costs			$ 818,000		$ 749,000	3,702,000	$ 1,381,000
Term Loan | Term Loan B Facility
Business Acquisition [Line Items]
Debt instrument, face amount	$ 250,000,000
Term Loan | Par Pacific Term Loan
Business Acquisition [Line Items]
Debt instrument, face amount								$ 45,000,000
Washington Acquisition
Business Acquisition [Line Items]
Consideration transferred, gross	$ 358,000,000
Oil and gas refinery capacity | mbpd	42
Oil and gas storage capacity | bbl	2.9
Consideration transferred	$ 327,400,000
Cash consideration transferred	$ 290,400,000
Common stock offering, net of issuance costs (in shares) | shares	2.4
Acquisition and integration costs		$ 5,400,000				2,200,000
Adjustment, property, plant, and equipment			2,100,000
Adjustment, deferred tax liability			5,900,000
Adjustment, working capital adjustment			(2,800,000)
Goodwill, purchase accounting adjustments			(5,200,000)
Revenue			$ 309,800,000			555,600,000
Earnings (loss) of acquiree since acquisition date, actual					$ 23,200,000	$ 20,100,000