	December 31,		December 31,
	2019		2018
Loan Agreement	$	—	$	—
4.67% Senior Unsecured Notes due January 15, 2021		40,000		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
		78,000		78,000
Less unamortized deferred financing costs		824		1,210
	$	77,176	$	76,790

In March 2017, the Company entered into a Fifth Amended and Restated Loan Agreement (the “Loan Agreement”). The Loan Agreement amended the pre-existing senior revolving credit facility’s borrowing limit to $200 million, inclusive of letters of credit, and extended the maturity date from December 2018 to March 2022. As of December 31, 2019, the Company had $194.2 million available under the Loan Agreement after $5.8 million of letters of credit issued related to insurance and other financing contracts in the ordinary course of business, including the $2 million provided to the EPA as discussed in Note 12. Borrowings under the Loan Agreement bear interest at the LIBOR rate, prime rate, federal funds effective rate, the Canadian deposit offered rate, or the eurocurrency reference rate depending on the type of loan requested by the Company, in each case plus the applicable margin as set forth in the Loan Agreement.

The Company’s Senior Unsecured Notes (“Notes”) range in face value from $11 million to $40 million, with interest rates ranging from 4.67% to 5.45%, payable semiannually, and maturing between 2021 and 2026. In September 2017, the Company offered to all Note holders to purchase all or a portion of the then-outstanding $100 million Notes prior to their maturity dates. In October 2017, one note holder accepted the offer and elected to tender $22 million in Notes. The Company purchased the Notes from the holder on October 31, 2017 for approximately $23.8 million, which includes the outstanding principal balance of $22.0 million and a make-whole premium of $1.8 million. A loss on extinguishment of debt of approximately $1.9 million was recorded during 2017, which consisted of the make-whole premium plus unamortized deferred financing costs of $0.1 million.

Amortization expense of the deferred financing costs was $386, $386, and $508 for the years ended December 31, 2019, 2018 and 2017, respectively, and is included in interest expense.

The weighted average interest rate on borrowings under the Company’s loan agreements were 6.27% for 2019, 5.75% for 2018, and 4.94% for 2017, which includes a quarterly facility fee on the used and unused portion, as well as amortization of deferred financing costs.

As of December 31, 2019, 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 an interest coverage ratio (defined as earnings before interest, taxes, depreciation and amortization, as adjusted, divided by interest expense) and a leverage ratio (defined as total debt divided by earnings before interest, taxes, depreciation and amortization, as adjusted). The ratios as of December 31, 2019 are shown in the following table:

	Required Level	Actual Level
Interest Coverage Ratio	3.00 to 1 (minimum)		14.26
Leverage Ratio	3.25 to 1 (maximum)		1.20