Acquisitions - Washington Acquisition (Details) bbl / d in Thousands, MBbls / d in Thousands, shares in Millions, bbl in Millions		1 Months Ended	3 Months Ended			9 Months Ended
	Jan. 11, 2019 USD ($) MBbls / d shares bbl	Jan. 31, 2019 USD ($)	Sep. 30, 2020 USD ($) bbl / d	Sep. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Sep. 30, 2020 USD ($) bbl / d	Sep. 30, 2019 USD ($)	Jan. 09, 2019 USD ($)
Business Acquisition [Line Items]
Oil and gas refinery capacity (in Mbpd) | bbl / d			200			200
Issuance of common stock for business combination	$ 37,000,000.0				$ 36,980,000
Acquisition and integration costs			$ (155,000)	$ 623,000		$ 600,000	$ 4,325,000
Income tax benefit			$ (108,000)	2,428,000		$ 20,855,000	69,002,000
Term Loan | Term Loan B
Business Acquisition [Line Items]
Debt instrument, face amount	$ 250,000,000.0
Term Loan | Par Pacific Term Loan
Business Acquisition [Line Items]
Debt instrument, face amount								$ 45,000,000.0
Washington Acquisition
Business Acquisition [Line Items]
Oil and gas refinery capacity (in Mbpd) | MBbls / d	42
Oil and gas storage capacity (in mmbbl) | bbl	2.9
Consideration transferred	$ 326,500,000
Cash consideration transferred	$ 289,500,000
Common stock offering, net of issuance costs (in shares) | shares	2.4
Acquisition and integration costs		$ 5,400,000					2,200,000
Revenue				300,000,000.0			855,600,000
Earnings (loss) of acquiree since acquisition date, actual				$ 29,400,000			49,500,000
Income tax benefit							$ 67,000,000.0