Debt

Long-term debt as of March 31, 2019 and December 31, 2018 consists of the following:



(in thousands)	March 31, 2019			December 31, 2018
Senior secured notes, due 2024	$	350,000		$	350,000
Revolving credit agreement	—			—
	350,000			350,000
Unamortized debt issuance costs related to senior secured notes	(4,595		)	(4,803		)
	345,405			345,197
Less: Current portion of long-term debt	—			—
	$	345,405		$	345,197

Senior Secured Notes

On September 15, 2016, the Company issued $350.0 million of senior secured notes due 2024 (the “Senior Notes”) under an unregistered private placement not subject to the registration requirements of the Securities Act of 1933, as amended (the “Securities Act”). The Senior Notes were issued by BMC East, LLC, a 100% owned subsidiary of the Company, and are guaranteed by the Company and the other subsidiaries that guarantee the Credit Agreement (as defined below). Each of the subsidiary guarantors is 100% owned, directly or indirectly, by the Company, and all guarantees are full and unconditional and joint and several. The interest rate is fixed at 5.5% and is payable semiannually on April 1 and October 1.

As of March 31, 2019, the estimated market value of the Senior Notes was approximately $6.1 million lower than the carrying amount. The fair value is based on institutional trading activity and was classified as a Level 2 measurement in accordance with ASC 820.

Revolving Credit Agreement

On December 1, 2015, the Company entered into a senior secured credit agreement with Wells Fargo Capital Finance, as administrative agent, and certain other lenders (the “Original Credit Agreement”), which includes a revolving line of credit (the “Revolver”). The Original Credit Agreement, as amended (the “Credit Agreement”), has an aggregate commitment of $375.0 million. The Company had no outstanding borrowings under the Revolver and net availability of $317.7 million as of March 31, 2019. The Company had $56.1 million in letters of credit outstanding under the Credit Agreement as of March 31, 2019.