(In thousands)	Maturity Dates	December 31, 2020		December 31, 2019
Unsecured private placement notes
3.95% (net of unamortized debt issuance cost of $273 and $316 for 2020 and 2019, respectively)	2021-2027	$	99,727	$	99,684
3.86% (net of unamortized debt issuance cost of $236 and $291 for 2020 and 2019, respectively)	2021-2025		71,193		85,423
4.86% (net of unamortized debt issuance cost of $108 and $147 for 2020 and 2019, respectively)	2021-2023		27,749		36,996
Total debt		$	198,669	$	222,103
Less current maturities			37,857		23,571
Long-term debt		$	160,812	$	198,532

The Company’s long-term debt financing is currently composed of unsecured private placement notes issued to insurance companies, totaling $199,286,000 as of December 31, 2020. These notes are denominated in U.S. dollars and have fixed interest rates ranging from 3.86 percent to 4.86 percent. The notes had original maturities of 12 years with mandatory amortization of principal beginning six years after issuance. The Company will be required to make amortization payments on the currently outstanding notes from 2021 to 2027.

The Company has a committed $350,000,000 multi-currency revolving credit agreement that expires on January 30, 2023. The Company maintains standby letters of credit under its workers’ compensation insurance agreements and for other purposes, as needed from time to time, which are issued under the revolving credit agreement. As of December 31, 2020, the Company had outstanding letters of credit totaling $6,220,000 and no borrowings under the revolving credit agreement. There was $343,780,000 available under the revolving credit agreement as of December 31, 2020.

Loans under the credit agreement may be incurred, at the discretion of the Company, with terms to maturity of one to six months. The Company may choose from two interest rate options: (1) LIBOR applicable to each currency plus spreads ranging from 1.25 percent to 1.875 percent, depending on the Company’s net leverage ratio, or (2) the prime rate plus 0.25 percent to 0.875 percent, depending on the Company’s net leverage ratio. The credit agreement requires the Company to pay a commitment fee ranging from 0.15 percent to 0.325 percent per annum, which also depends on the Company’s net leverage ratio. The credit agreement requires the maintenance of certain financial ratios and compliance with certain other covenants that are similar to the Company’s existing debt agreements, including net worth, interest coverage and leverage financial covenants and limitations on restricted payments, indebtedness and liens.

The Company’s foreign subsidiaries had no unsecured debt at December 31, 2020.

The Company’s loan agreements contain provisions, which, among others, require maintenance of certain financial ratios and place limitations on additional debt, investments and payment of dividends. Based on the loan agreement provisions that place limitations on dividend payments, unrestricted retained earnings (i.e., retained earnings available for dividend distribution) were $373,884,000 and $283,956,000 at December 31, 2020 and 2019, respectively.

Debt at December 31, 2020, matures as follows: $37,857,000 in 2021; $37,857,000 in 2022; $37,857,000 in 2023; $28,572,000 in 2024; $28,572,000 in 2025 and $28,571,000 after 2025. Debt maturing in 2021 includes $37,857,000 of scheduled repayments under long-term debt agreements. Although the Company’s foreign subsidiaries currently have no short-term working capital loans,

these types of loans routinely exist. These short-term loan agreements could be supplemented, if necessary, by the Company’s $350,000,000 revolving credit agreement entered into on January 30, 2018.

Net interest expense for the years ended December 31, 2020, 2019 and 2018, comprised the following:

(In thousands)	2020			2019			2018
Interest expense	$	9,859		$	12,744		$	13,360
Interest income		(2,171	)		(5,717	)		(1,829	)
		7,688			7,027			11,531
Capitalized interest		(2,279	)		(1,095	)		(760	)
Interest expense, net	$	5,409		$	5,932		$	10,771