Quarterly report pursuant to Section 13 or 15(d)

Revenue Recognition (Performance Obligation) (Details)

Revenue Recognition (Performance Obligation) (Details)
9 Months Ended
Sep. 30, 2018
Revenue from Contract with Customer [Abstract]  
Performance obligation, description of timing The Company records revenue in the month production is delivered to the purchaser. However, settlement statements for sales may not be received for 30 to 90 days after the date production is delivered, and as a result, the Company is required to estimate the amount of production delivered to the purchaser and the price that will be received for the sale of the product.