(10) Long-Term Debt

Long-term debt to unrelated entities consisted of the following (in thousands):



	March 31,		December 31,
	2018		2017
Note payable to a financial institution, with interest only payment until maturity	$	—	$	—
Installment notes bearing interest at the rate of 4.16% to 4.60% per annum collateralized by vehicles with monthly payments including interest, insurance and maintenance of approximately $10		159		90
Total debt		159		90
Less current maturities		(56)		(41)
Long-term debt, less current maturities	$	103	$	49

At March 31, 2018, the Company had a revolving credit facility with Prosperity Bank. This has historically been the Company’s primary source to fund working capital and future capital spending. Under the credit facility, loans and letters of credit are available to the Company on a revolving basis in an amount outstanding not to exceed the lesser of $50 million or the Company’s borrowing base in effect from time to time. As of March 31, 2018, the Company’s borrowing base was $2 million. The credit facility is secured by substantially all of the Company’s producing and non-producing oil and gas properties. The credit facility includes certain covenants with which the Company is required to comply. At March 31, 2018, these covenants include the following: (a) Current Ratio > 1:1; (b) Funded Debt to EBITDA < 3.5x; and (c) Interest Coverage > 3.0x. At March 31, 2018, the interest rate on this credit facility was 5.25%. The Company was in compliance with all covenants during the quarter ended March 31, 2018.

On March 21, 2018, the Company’s senior credit facility with Prosperity Bank after Prosperity Bank’s most recent review of the Company’s currently owned producing properties was amended to increase the borrowing base to $2 million and the maturity date was extended to July 31, 2020. The borrowing base remains subject to the existing periodic redetermination provisions in the credit facility. The interest rate remained prime plus 0.50% per annum. This rate was 5.00% at the date of the amendment. The maximum line of credit of the Company under the Prosperity Bank credit facility remained $50 million and the Company had no outstanding borrowing under the facility as of March 31, 2018. The next borrowing base review will take place in July 2018.