Income Taxes	9 Months Ended
Sep. 30, 2017
Income Taxes [Abstract]
Income Taxes	(8)Income Taxes Our effective tax rate (ETR) was estimated at 8% and 15% for the nine months ended September 30, 2017 and 2016, respectively. Assuming no changes in our expected results of operations, we expect our ETR for the remainder of 2017 to be about the same as the first nine months of 2017. Our ETR differs from the statutory rate due primarily to statutory depletion in excess of tax basis, which is a permanent difference.

Income Taxes

9 Months Ended

Sep. 30, 2017

(8)Income Taxes

Our effective tax rate (ETR) was estimated at 8% and 15% for the nine months ended September 30, 2017 and 2016, respectively. Assuming no changes in our expected results of operations, we expect our ETR for the remainder of 2017 to be about the same as the first nine months of 2017. Our ETR differs from the statutory rate due primarily to statutory depletion in excess of tax basis, which is a permanent difference.