Significant Concentrations	12 Months Ended
Dec. 31, 2015
Risks and Uncertainties [Abstract]
Significant Concentrations	Significant Concentrations Major customers. For the year ended December 31, 2015, sales to Shell Trading (US) Company accounted for approximately 10% of the Company’s total sales. For the years ended December 31, 2014 and 2013, sales to Musket Corporation accounted for approximately13% and 11% of the Company’s total sales, respectively. No other purchasers accounted for more than 10% of the Company’s total sales for the years ended December 31, 2015, 2014 and 2013. Total sales include revenues from the Company’s exploration and production segment only, as OWS and OMS provide services to OPNA. Substantially all of the Company’s accounts receivable result from sales of oil and natural gas as well as joint interest billings (“JIB”) to third-party companies who have working interest payment obligations in projects completed by the Company. Statoil Oil & Gas LP and HRG, Inc. accounted for approximately 17% and 10%, respectively, of the Company’s JIB receivables balance at December 31, 2015. Statoil Oil & Gas LP, Continental Resources, Inc. and Slawson Exploration Company, Inc. accounted for approximately 16%, 14% and 13%, respectively, of the Company’s JIB receivables balance at December 31, 2014. This concentration of customers and joint interest owners may impact the Company’s overall credit risk, either positively or negatively, in that these entities may be similarly affected by changes in economic or other conditions, including the current downturn in oil prices. Management believes that the loss of any of these purchasers would not have a material adverse effect on the Company’s operations, as there are a number of alternative oil and natural gas purchasers in the Company’s producing regions.

Significant Concentrations

Major customers. For the year ended December 31, 2015, sales to Shell Trading (US) Company accounted for approximately 10% of the Company’s total sales. For the years ended December 31, 2014 and 2013, sales to Musket Corporation accounted for approximately13% and 11% of the Company’s total sales, respectively. No other purchasers accounted for more than 10% of the Company’s total sales for the years ended December 31, 2015, 2014 and 2013. Total sales include revenues from the Company’s exploration and production segment only, as OWS and OMS provide services to OPNA.

Substantially all of the Company’s accounts receivable result from sales of oil and natural gas as well as joint interest billings (“JIB”) to third-party companies who have working interest payment obligations in projects completed by the Company. Statoil Oil & Gas LP and HRG, Inc. accounted for approximately 17% and 10%, respectively, of the Company’s JIB receivables balance at December 31, 2015. Statoil Oil & Gas LP, Continental Resources, Inc. and Slawson Exploration Company, Inc. accounted for approximately 16%, 14% and 13%, respectively, of the Company’s JIB receivables balance at December 31, 2014.

This concentration of customers and joint interest owners may impact the Company’s overall credit risk, either positively or negatively, in that these entities may be similarly affected by changes in economic or other conditions, including the current downturn in oil prices. Management believes that the loss of any of these purchasers would not have a material adverse effect on the Company’s operations, as there are a number of alternative oil and natural gas purchasers in the Company’s producing regions.