	March 31,		December 31,
	2021		2020
Loan Agreement	$	33,000	$	—
4.67% Senior Unsecured Notes due January 15, 2021		—		40,000
5.25% Senior Unsecured Notes due January 15, 2024		11,000		11,000
5.30% Senior Unsecured Notes due January 15, 2024		15,000		15,000
5.45% Senior Unsecured Notes due January 15, 2026		12,000		12,000
		71,000		78,000
Less unamortized deferred financing costs		72		424
		70,928		77,576
Less current portion long-term debt		—		39,994
Long-term debt	$	70,928	$	37,582

In March 2021, the Company entered into a Sixth Amended and Restated Loan Agreement (the “Sixth Amendment”), which amended the Fifth Amended and Restated Loan Agreement (collectively, the “Loan Agreement”) dated March 2017. The Sixth Amendment increased the senior revolving credit facility’s borrowing limit to $250 million from $200 million, extended the maturity date to March 2024 from March 2022, and increased flexibility of the financial and other covenants and provisions. Amounts borrowed under the credit facility are secured by pledges of stock of certain of the Company’s foreign subsidiaries and guaranties of certain of its domestic subsidiaries. In connection with the Sixth Amendment, the Company incurred $1.1 million of deferred financing fees, which are included in Other Assets (long-term).

As of March 31, 2021, the Company had $211.2 million available under the Loan Agreement. The Company had $5.8 million of letters of credit issued related to insurance and other contracts requiring financial assurance in the ordinary course of business, including the $2 million provided to the EPA as discussed in Note 11. Borrowings under the Loan Agreement bear interest at the LIBOR rate, prime rate, federal funds effective rate, the Canadian deposit offered rate, or the euro currency reference rate depending on the type of loan requested by the Company, plus the applicable margin as set forth in the Loan Agreement.

The Company also holds Senior Unsecured Notes (“Notes”), which range in face value from $11.0 million to $15.0 million, with interest rates ranging from 5.25% to 5.45%, payable semiannually, and maturing between January 2024 and January 2026. At March 31, 2021, $38.0 million of the Notes were outstanding. In January 2021, the Company repaid the $40.0 million note upon maturity with a combination of cash and proceeds under the Loan Agreement.

The weighted average interest rate on borrowings under the Company’s long-term debt was 5.33% and 6.24% for the quarters ended March 31, 2021 and 2020, respectively, which includes a quarterly facility fee on the used and unused portion, as well as amortization of deferred financing costs.

As of March 31, 2021, the Company was in compliance with all of its debt covenants associated with its Loan Agreement and Notes. The most restrictive financial covenants for all of the Company’s debt are a leverage ratio (defined as total debt divided by earnings before interest, taxes, depreciation and amortization, as adjusted) and an interest coverage ratio (defined as earnings before interest, taxes, depreciation and amortization, as adjusted, divided by interest expense).