Debt and Credit Facility

6 Months Ended

Jun. 30, 2019

Debt Disclosure [Abstract]

Debt and Credit Facility

Debt and Credit Facility

Senior Notes

In May 2016, we issued $375.0 million principal amount of 5.875% unsecured senior notes due May 15, 2024 ("Senior Notes") at 100% of the principal amount. The unamortized amount of debt issuance costs as of June 30, 2019 was $4.1 million. Interest expense, including amortization of debt issuance costs, relating to the Senior Notes was $5.7 million for each of the quarters ended June 30, 2019 and June 30, 2018. Interest expense, including amortization of debt issuance costs, relating to the Senior Notes was $11.4 million for each of the six months ended June 30, 2019 and June 30, 2018. A portion of the interest relating to the Senior Notes was capitalized as construction in progress. The effective interest rate of the Senior Notes is approximately 6.1% per annum, taking into account the amortization of debt issuance costs. The fair value of the outstanding Senior Notes, which are Level 1 liabilities, was approximately $390.1 million and $369.9 million at June 30, 2019 and December 31, 2018, respectively.

Revolving Credit Facility

Our credit agreement with JPMorgan Chase Bank, N.A., as administrative agent, and the other financial institutions party thereto ("Revolving Credit Facility") provides us with a $300.0 million funding commitment through December 2020. We had $300.0 million of borrowing availability under the Revolving Credit Facility at June 30, 2019, based on the borrowing base determination then in effect. At June 30, 2019, there were no borrowings under the Revolving Credit Facility and $8.0 million was being used to support outstanding letters of credit, leaving $292.0 million of net borrowing availability. The interest rate applicable to any overnight borrowings under the Revolving Credit Facility would have been 5.75% at June 30, 2019.