Debt

The following table summarizes our outstanding debt:



	March 31, 2019			December 31, 2018			Interest Rate	Maturity	Security
	(in thousands)
RBL Facility	$	—		$	—		variable rates of 6.25% (2019) and 4.5% (2018), respectively	June 29, 2022	Mortgage on 85% of Present Value of proven oil and gas reserves and lien on other assets
2026 Senior Unsecured Notes	400,000			400,000			7.00%	February 15, 2026	Unsecured
Long-Term Debt - Principal Amount	400,000			400,000
Less: Debt Issuance Costs	(8,053		)	(8,214		)
Long-Term Debt, net	$	391,947		$	391,786

Deferred Financing Costs

We incurred legal and bank fees related to the issuance of debt. At March 31, 2019 and December 31, 2018, debt issuance costs for the RBL Facility (as defined below) reported in "other noncurrent assets" on the balance sheet were approximately $15 million and $16 million net of amortization, respectively. The amortization of debt issuance costs is presented in interest expense on the condensed consolidated statements of operations. At March 31, 2019 and December 31, 2018, debt issuance costs for the 2026 Senior Unsecured Notes were $8 million and $8 million net of amortization, respectively.

For the three months ended March 31, 2019 and March 31, 2018, amortization expense of approximately $1 million and $1 million, respectively, was included in “interest expense” in the condensed consolidated statements of operations.

Fair Value

Our debt is recorded at the carrying amount on the balance sheets. The carrying amount of the RBL Facility approximates fair value because the interest rates are variable and reflect market rates. The fair value of the 2026 senior unsecured notes was approximately $399 million and $368 million at March 31, 2019 and December 31, 2018, respectively.

The RBL Facility

On July 31, 2017, we entered into a credit agreement (“RBL Facility”), with Wells Fargo Bank, N.A. as administrative agent and certain lenders with up to $1.5 billion of commitments, subject to a reserves-based borrowing base. In April 2019, we completed a borrowing base redetermination under our RBL Facility that resulted in our borrowing base being set at $750 million and we reaffirmed our elected commitment amount at $400 million. The RBL Facility matures on July 29, 2022, unless terminated earlier in accordance with the RBL Facility terms.

We were in compliance with all financial covenants as of March 31, 2019.

As of March 31, 2019, we had approximately $391 million of available borrowing capacity under the RBL Facility.

As of March 31, 2019 and December 31, 2018, we had letters of credit outstanding of approximately $9 million and $7 million, respectively, under our RBL facility. These letters of credit were issued to support ordinary course of business marketing, insurance, regulatory and other matters.