5.  Long-Term Debt

Our long-term debt was as follows (in thousands):

At September 30, 2015 and December 31, 2014, our outstanding senior notes, which bear an annual interest rate of 8.50% and mature on June 15, 2019 (the “8.50% Senior Notes”), were classified as long-term at their carrying value.  Interest on the 8.50% Senior Notes is payable semi-annually in arrears on June 15 and December 15.  The estimated annual effective interest rate on the 8.50% Senior Notes is 8.4%, which includes amortization of debt issuance costs and premiums.  The debt premiums, net of amortization, are related to the 8.50% Senior Notes.  We are subject to various financial and other covenants under the indenture governing the 8.50% Senior Notes, and we were in compliance with those covenants as of September 30, 2015.  

In May 2015, we entered into the 9.00% Term Loan, which has a principal of $300.0 million, bears an annual interest rate of 9.00%, was issued at a 1% discount to par and matures on May 15, 2020.  The 9.00% Term Loan is secured by a second priority lien covering our oil and gas properties to the extent such properties secure first priority liens granted to secure indebtedness under our Credit Agreement.  Interest on the 9.00% Term Loan is payable in arrears semi-annually on May 15 and November 15.  The estimated annual effective interest rate on the 9.00% Term Loan is 9.7%, which includes amortization of debt issuance costs and discounts.  The net proceeds were used to repay a portion of the outstanding borrowings incurred under our revolving bank credit facility governed by the Credit Agreement.  An entity controlled by the Company’s Chairman and Chief Executive Officer participated in the 9.00% Term Loan for a $5.0 million principal commitment on the same terms as the other lenders.  We are subject to various covenants under the terms governing the 9.00% Term Loan including, without limitation, covenants that limit our ability to incur other debt, pay dividends or distributions on our equity, merge or consolidate with other entities and make certain investments in other entities.  We were in compliance with those covenants as of September 30, 2015.  

Our revolving bank credit facility governed by the Credit Agreement matures on November 8, 2018.  Borrowings under our revolving bank credit facility are secured by our oil and natural gas properties.  Availability under such facility is subject to a semi-annual redetermination of our borrowing base that occurs in the spring and fall of each year and is calculated by our lenders based on their evaluation of our proved reserves and their own internal criteria.  

At both September 30, 2015 and December 31, 2014, we had $0.9 million of letters of credit outstanding under the revolving bank credit facility.  The estimated annual effective interest rate was 3.3% for the nine months ended September 30, 2015 for average daily borrowings under the revolving bank credit facility.  The estimated annual effective interest rate includes amortization of debt issuance costs and excludes commitment fees and other costs.  As of September 30, 2015, our borrowing base was $500.0 million and our borrowing availability was $234.1 million.  See Note 12 for the results of the semi-annual redetermination and an amendment to the Credit Agreement subsequent to September 30, 2015.  

Through September 30, 2015, we have entered into two amendments to the Credit Agreement.  Following is a summary of the primary terms of the amendments:

The foregoing description of the Credit Agreement does not purport to be complete and is qualified in its entirety by reference to the agreement.

During the second quarter of 2015, the borrowing base on the revolving bank credit facility was reduced after the semi-annual redetermination and further reduced in conjunction with the issuance of the 9.00% Term Loan pursuant to the terms of the Credit Agreement.  The reductions in the borrowing base resulted in proportional reductions in the unamortized debt issuance costs of $2.0 million related to the Credit Agreement, which is recorded within the line Other (income) and expense, net on the Statements of Operations.  

Under the Credit Agreement, we are subject to various financial covenants, as listed above, which are calculated as of the last day of each fiscal quarter.  We were in compliance with all applicable covenants of the Credit Agreement as of September 30, 2015.

See Note 12 for information on the third amendment and changes to the borrowing base subsequent to September 30, 2015.

For information about fair value measurements for our 8.50% Senior Notes, 9.00% Term Loan and revolving bank credit facility, refer to Note 6.