Debt

Senior notes. Unsecured senior debt, net of unamortized discounts and debt issuance costs, as of January 30, 2016 and January 31, 2015 consisted of the following:



($000)	2015		2014
6.38% Series A Senior Notes due 2018	$	84,906	$	84,873
6.53% Series B Senior Notes due 2021	64,882		64,861
3.375% Senior Notes due 2024	246,237		245,828
Total	$	396,025	$	395,562

In September 2014, the Company issued 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 January 30, 2016, 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 January 30, 2016, the Company was in compliance with these covenants.

As of January 30, 2016 and January 31, 2015, total unamortized discount and debt issuance costs were $4.0 million and $4.4 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 $423 million and $442 million as of January 30, 2016 and January 31, 2015, 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)
2016	$	—
2017	$	—
2018	$	85,000
2019	$	—
2020	$	—
Thereafter	$	315,000

The table below shows the components of interest expense and income for fiscal 2015, 2014, and 2013:



($000)	2015			2014			2013
Interest expense on long-term debt	$	18,568		$	12,990		$	9,721
Other interest expense	1,252			1,230			1,350
Capitalized interest	(6,530		)	(10,825		)	(10,799		)
Interest income	(678		)	(411		)	(519		)
Interest expense (income), net	$	12,612		$	2,984		$	(247	)

Revolving credit facility. The Company's $600 million unsecured revolving credit facility expires in June 2017 and contains a $300 million sublimit for issuance of standby letters of credit. Interest on this facility is based on LIBOR plus an applicable margin (currently 100 basis points) and is payable quarterly and upon maturity. As of January 30, 2016 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 Company plans to renew the revolving credit facility in 2016.

The revolving credit facility is subject to certain financial covenants, including interest coverage and other financial ratios. In addition, the interest rates under the revolving credit facility may vary depending on actual interest coverage ratios achieved. As of January 30, 2016, the Company was in compliance with these covenants.

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 January 30, 2016 and January 31, 2015, the Company had $15.3 million and $19.5 million, respectively, in standby letters of credit and $56.4 million and $56.3 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 $32.0 million and $32.8 million in trade letters of credit outstanding at January 30, 2016 and January 31, 2015, respectively.