Acquisitions - Washington Acquisition (Details) $ / shares in Units, mbpd in Thousands, barrel / d in Thousands, shares in Millions, bbl in Millions		1 Months Ended	3 Months Ended
	Jan. 11, 2019 USD ($) mbpd shares bbl	Jan. 31, 2019 USD ($)	Mar. 31, 2020 USD ($) barrel / d	Mar. 31, 2019 USD ($) $ / shares	Jan. 09, 2019 USD ($)
Business Acquisition [Line Items]
Oil and gas refinery capacity (in Mbpd) | barrel / d			200
Issuance of common stock for business combination	$ 37,000,000.0			$ 36,980,000
Acquisition and integration costs			$ 665,000	2,884,000
Income tax expense (benefit)			18,247,000	64,769,000
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) | mbpd	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			245,800,000
Earnings (loss) of acquiree since acquisition date, actual			$ (3,100,000)
Income tax expense (benefit)				65,400,000
Net income (loss)				$ 65,600,000
Pro forma earnings per share, basic (in dollars per share) | $ / shares				$ 1.35
Pro forma earnings per share, diluted (in dollars per share) | $ / shares				$ 1.24