6. Debt

Debt comprised the following at December 31, 2017 and 2016:

(In thousands)	Maturity Dates	December 31, 2017		December 31, 2016
Unsecured private placement notes
3.95% (net of unamortized debt issuance cost of $346 and $382 for 2017 and 2016, respectively)	2021-2027	$	99,654	$	99,618
3.86% (net of unamortized debt issuance cost of $343 and $390 for 2017 and 2016, respectively)	2019-2025		99,657		99,610
4.86% (net of unamortized debt issuance cost of $191 and $225 for 2017 and 2016, respectively)	2018-2023		55,523		64,775
5.88% (net of unamortized debt issuance cost of $95 and $116 for 2017 and 2016, respectively)	2018-2022		28,476		34,170
5.69% (net of unamortized debt issuance cost of $12 and $28 for 2017 and 2016, respectively)	2018		5,703		11,400
Debt of foreign subsidiaries
Unsecured bank debt, foreign currency	2018		1,786		432
Secured bank debt, foreign currency	2018		—		7,008
Total debt		$	290,799	$	317,013
Less current maturities			22,500		28,154
Long-term debt		$	268,299	$	288,859

The majority of the Company’s long-term debt financing is composed of unsecured private placement notes issued to insurance companies, totaling $290,000,000 as of December 31, 2017. These notes are denominated in U.S. dollars and have fixed interest rates ranging from 3.86 percent to 5.88 percent. At inception, these notes had final maturities of 12 to 13 years with remaining amortization scheduled from 2018 to 2027.

At December 31, 2017 the Company had a committed $125,000,000 multi-currency five-year revolving credit agreement. This unsecured facility was the Company’s primary source of short-term borrowings and the Company was able to draw on this agreement as needed to finance certain acquisitions, working capital and for general corporate purposes. This facility was scheduled to expire on July 10, 2019. On December 31, 2017, the Company had outstanding letters of credit of $4,677,000 and no borrowings under this agreement with $120,323,000 remaining available. On January 30, 2018, the Company entered into a five year committed $350,000,000 multi-currency revolving credit facility that matures on January 30, 2023 with a syndicate of banks. This credit facility replaced the Company’s prior $125,000,000 credit agreement. See Note 26 - Subsequent Events for more details.

Loans under the credit agreement in place at December 31, 2017 could have been incurred, at the discretion of the Company, with terms to maturity of 1 to 180 days. The Company may have chosen from several interest rate options, including (1) LIBOR applicable to each currency plus spreads ranging from 0.975 percent to 1.525 percent, depending on the Company’s leverage ratio or (2) the prime rate plus zero percent to 0.525 percent, depending on the leverage ratio. The credit agreement required the Company to pay a facility fee ranging from 0.150 percent to 0.350 percent, which also depended on the leverage ratio. The credit agreement required 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.

In addition to the unsecured private placement notes and the revolving credit facility, the Company’s foreign subsidiaries had $1,786,000 of unsecured debt at December 31, 2017.

The Company’s loan agreements in the U.S. and Philippines 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 $190,495,000 and $157,606,000 at December 31, 2017, and 2016, respectively.

Debt at December 31, 2017, matures as follows: $22,500,000 in 2018; $29,286,000 in 2019; $29,286,000 in 2020; $43,572,000 in 2021; $43,572,000 in 2022 and $123,570,000 after 2022. Debt maturing in 2018 includes $20,714,000 of scheduled repayments under long-term debt agreements and $1,786,000 of debt of foreign subsidiaries under short-term working capital loans. These short-term loan agreements are routinely renewed, but could be supplemented or replaced, 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, 2017, 2016 and 2015, comprised the following:

(In thousands)	2017			2016			2015
Interest expense	$	14,428		$	15,240		$	15,488
Interest income		(2,075	)		(1,247	)		(217	)
		12,353			13,993			15,271
Capitalized interest		(909	)		(788	)		(738	)
Interest expense, net	$	11,444		$	13,205		$	14,533