Major Customers (Tables)

12 Months Ended

Dec. 31, 2019

Risks and Uncertainties [Abstract]

Schedule of revenue by major customer

Purchasers of the Company's oil, NGL and gas production that individually accounted for ten percent or more of the Company's oil and gas revenues in at least one of the three years ended December 31, 2019 are as follows:

	Year Ended December 31,
	2019		2018		2017
Sunoco Logistics Partners L.P.	33	%	28	%	21	%
Occidental Energy Marketing Inc.	20	%	17	%	16	%
Plains Marketing L.P.	13	%	15	%	14	%
Enterprise Products Partners L.P.	1	%	6	%	11	%

Schedule of sales of purchased oil, NGL and gas revenues

Purchasers of the Company's purchased oil and gas that individually accounted for ten percent or more of the Company's sales of purchased oil and gas in at least one of the three years ended December 31, 2019 are as follows:

	Year Ended December 31,
	2019		2018		2017
Occidental Energy Marketing Inc.	30	%	34	%	39	%
BP Energy	5	%	9	%	11	%
Exxon Mobil	4	%	5	%	11	%
Valero Marketing and Supply Company	2	%	9	%	14	%