Debt

Senior notes. Unsecured senior debt, net of unamortized discounts and debt issuance costs, as of February 3, 2018 and January 28, 2017 consisted of the following:



($000)	2017		2016
6.38% Series A Senior Notes due 2018	$	84,973	$	84,939
6.53% Series B Senior Notes due 2021	64,922		64,902
3.375% Senior Notes due 2024	247,072		246,652
Total long-term debt	$	396,967	$	396,493

Less: current portion	84,973		—
Total due beyond one year	$	311,994	$	396,493

As of February 3, 2018, the Company had outstanding unsecured 3.375% Senior Notes due September 2024 (the “2024 Notes”) with an aggregate principal amount of $250 million. Interest on the 2024 Notes is payable semi-annually.

As of February 3, 2018, the Company also had outstanding two other series of unsecured senior notes in the aggregate principal amount of $150 million, held by various institutional investors. The Series A notes totaling $85 million are due in December 2018 and bear interest at a rate of 6.38%. The Series B notes totaling $65 million are due in December 2021 and bear interest at a rate of 6.53%. Borrowings under these senior notes are subject to certain financial covenants, including interest coverage and other financial ratios. As of February 3, 2018, the Company was in compliance with these covenants.

As of February 3, 2018 and January 28, 2017, total unamortized discount and debt issuance costs were $3.0 million and $3.5 million, respectively, and were classified as a reduction of long-term debt.

The 2024 Notes, Series A, and Series B senior notes are all subject to prepayment penalties for early payment of principal.

The aggregate fair value of the three outstanding senior note issuances was approximately $411 million and $419 million as of February 3, 2018 and January 28, 2017, respectively. The fair value is estimated by obtaining comparable market quotes which are considered to be Level 1 inputs under the fair value measurements and disclosures guidance.

The following table shows scheduled annual principal payments on Long-term debt:



($000)
2018	$	85,000
2019	$	—
2020	$	—
2021	$	65,000
2022	$	—
Thereafter	$	250,000

The table below shows the components of interest expense and income for fiscal 2017, 2016, and 2015:



($000)	2017			2016			2015
Interest expense on long-term debt	$	18,578		$	18,573		$	18,568
Other interest expense	979			1,022			1,252
Capitalized interest	(710		)	(26		)	(6,530		)
Interest income	(11,171		)	(3,081		)	(678		)
Interest expense, net	$	7,676		$	16,488		$	12,612

Revolving credit facility. The Company’s existing $600 million unsecured revolving credit facility expires in April 2021, and contains a $300 million sublimit for issuance of standby letters of credit (subject to increase in proportion to any increase in the size of the credit facility). The facility also contains an option allowing the Company to increase the size of its credit facility by up to an additional $200 million, with the agreement of the lenders. Interest on any borrowings under this facility is based on LIBOR plus an applicable margin (currently 100 basis points) and is payable quarterly and upon maturity. As of February 3, 2018, the Company had no borrowings or standby letters of credit outstanding under this facility and the $600 million credit facility remains in place and available.

The revolving credit facility is subject to a financial leverage ratio covenant. As of February 3, 2018, the Company was in compliance with this covenant.

Standby letters of credit and collateral trust. The Company uses standby letters of credit outside of its revolving credit facility in addition to a funded trust to collateralize its insurance obligations. As of February 3, 2018 and January 28, 2017, the Company had $8.7 million and $11.6 million, respectively, in standby letters of credit and $57.1 million and $56.6 million, respectively, in a collateral trust. The standby letters of credit are collateralized by restricted cash and the collateral trust consists of restricted cash, cash equivalents, and investments.

Trade letters of credit. The Company had $20.7 million and $26.5 million in trade letters of credit outstanding at February 3, 2018 and January 28, 2017, respectively.