Acquisitions - Washington Acquisition (Details) 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, 2019 USD ($) mbpd	Mar. 31, 2018 USD ($)	Jan. 09, 2019 USD ($)
Business Acquisition [Line Items]
Oil and gas refinery capacity | mbpd			200,000
Issuance of common stock			$ 36,980,000
Acquisition and integration costs			2,884,000	$ 632,000
Net income (loss)			61,092,000	$ 15,185,000
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	$ 326,400,000
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
Net income (loss)			$ (3,100,000)
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