(in thousands)	June 30, 2019		December 31, 2018			June 30, 2018
Senior notes payable	$	40,000	$	40,000		$	80,000
Credit Agreement term loan		142,500		146,250			150,000
Credit Agreement revolving credit loan		220,000		197,000			99,000
Convertible notes		—		—			160,765
Other		12,793		(845	)		(1,073	)
Total debt		415,293		382,405			488,692
Less current maturities		48,397		47,286			207,982
Total long-term debt	$	366,896	$	335,119		$	280,710

The aggregate minimum principal maturities of long-term debt, including current maturities and excluding debt issuance costs, related to balances at June 30, 2019 are as follows: $44.2 million during the remainder of 2019; $8.4 million in 2020; $8.5 million in 2021; $8.5 million in 2022; $337.3 in 2023 and $8.9 million in 2024 and thereafter.

Senior notes payable as of both June 30, 2019 and December 31, 2018 of $40.0 million and $80.0 million as of June 30, 2018 were due to a group of institutional holders and had an interest rate of 6.11% per annum (“2019 Notes”). As of June 30, 2019 and December 31, 2018, all of the $40.0 million was included in current maturities of long-term debt on the condensed consolidated balance sheets. As of June 30, 2018, $40.0 million of the outstanding balance was included in each of current maturities of long-term debt and long-term debt in the condensed consolidated balance sheets.

Granite entered into the Third Amended and Restated Credit Agreement dated May 31, 2018 (the “Credit Agreement”). The Credit Agreement provided for a $150.0 million term loan, of which $142.5 million was outstanding on June 30, 2019, and a $350.0 million revolving credit facility. We entered into the Amendment No. 1 to Third Amended and Restated Credit Agreement dated July 29, 2019 as discussed below.

The term loan requires that Granite repay 1.25% of the principal balance each quarter until the maturity date, at which point the remaining balance is due. As of each June 30, 2019, December 31, 2018 and June 30, 2018, $7.5 million of the term loan balance was included in current maturities of long-term debt on the condensed consolidated balance sheets and the remaining $135.0 million, $138.8 million and $142.5 million, respectively, was included in long-term debt.

As of June 30, 2019, the total stated amount of all issued and outstanding letters of credit under the Credit Agreement was $32.3 million. As of June 30, 2019, December 31, 2018, June 30, 2018, $220.0 million, $197.0 million, $99.0 million, respectively, was outstanding under the revolving credit facility. As of June 30, 2019, the total unused availability under the Credit Agreement was $97.7 million. The letters of credit will expire between July 2019 and June 2020.

Borrowings under the Credit Agreement bear interest at LIBOR or a base rate (at our option), plus an applicable margin based on the Consolidated Leverage Ratio (as defined in the Credit Agreement) calculated quarterly. The applicable margin was 1.75% for loans bearing interest based on LIBOR and 0.75% for loans bearing interest at the base rate at June 30, 2019. Accordingly, the effective interest rate using three-month LIBOR and base rate was 4.07% and 6.25%, respectively, at June 30, 2019 and we elected to use LIBOR for both the term loan and the revolving credit facility.

As of June 30, 2019, the conditions for the exercise of our right under Credit Agreement to have liens released were not satisfied.

Our Credit Agreement requires us to comply with various affirmative, restrictive and financial covenants. Our failure to comply with any of these covenants, or to pay principal, interest or other amounts when due thereunder, would constitute an event of default under the applicable agreements.

The most significant restrictive financial covenants under the terms of the Credit Agreement require the maintenance of a minimum Consolidated Interest Coverage Ratio and a maximum Consolidated Leverage Ratio. On July 29, 2019, the Company entered into Amendment No. 1 (the “Amendment”) to the Credit Agreement, which modified certain conditions of these financial covenants. As of June 30, 2019 and pursuant to the definitions in the Amendment and the Credit Agreement, the Consolidated Interest Coverage Ratio was 11.28, which exceeded the minimum of 4.00, and the Consolidated Leverage Ratio was 2.09, which did not exceed the maximum of 3.25.

As of June 30, 2019, we were compliant with the financial covenants contained in the Amendment No. 1 to Third Amended and Restated Credit Agreement. We called and redeemed the $40.0 million outstanding balance of the 2019 Notes on July 29, 2019 which were originally due in December 2019.