	March 31, 2020			December 31, 2019
Borrowings under the ABL Credit Facility	$	450.0		$	42.0
7.625% notes due June 15, 2020		64.5			65.8
7.875% notes due March 15, 2021		138.1			167.1
8.875% debentures due April 15, 2021		59.5			60.2
7.000% notes due February 15, 2022		133.4			140.0
6.500% notes due November 15, 2023		275.2			290.6
Term Loan due January 15, 2024 ^(a)		539.2			540.3
6.000% notes due April 1, 2024		251.8			298.3
6.625% debentures due April 15, 2029		149.8			157.9
8.500% notes due April 15, 2029		49.7			—
8.820% debentures due April 15, 2031		69.0			69.0
Unamortized debt issuance costs		(11.8	)		(12.8	)
Total debt		2,168.4			1,818.4
Less: current portion		208.1			71.2
Long-term debt	$	1,960.3		$	1,747.2

The fair values of the notes and debentures, which were determined using the market approach based upon quoted prices or interest rates available to us for debt obligations with similar terms and maturities, were determined to be Level 2 under the fair value hierarchy. The fair value of our total debt was less than its book value by approximately $35.9 million at March 31, 2020 and greater than its book value by approximately $29.3 million at December 31, 2019.

In March 2020, we entered into privately negotiated agreements with the largest holder of our outstanding notes (the “Seller”) to effect a series of refinancing transactions that address a significant portion of the Company’s 2023 and 2024 debt maturities. The agreements included the repurchase of $6.6 million of the 7.00% notes due 2022 and $20.0 million of the 6.00% notes due 2024. We funded these repurchases with a draw from our ABL Credit Facility. We recorded a gain of $0.2 million on these repurchases.

The agreements also included an exchange of $277.0 million aggregate principal amount of notes owned by the Seller, consisting of $54.0 million of the 6.50% notes due 2023 (the “2023 Notes”), $177.4 million of the 6.00% notes due in 2024 (the “2024 Notes”), and $45.6 million of the 6.625% debentures due 2029 (the “2029 Debentures”) for $297.0 million aggregate principal amount of newly issued unsecured 8.50% notes due 2029 (the “New 2029 Notes”). Other than the interest rate, the terms of the New 2029 Notes are substantially similar to the terms of the 2029 Debentures. As of March 31, 2020, only a portion of this exchange was completed including $15.4 million of the 2023 Notes, $26.5 million of the 2024 Notes, and $8.1 million of the 2029 Debentures, which were exchanged for $53.6 million aggregate principal of New 2029 Notes. We treated the transaction as a debt modification, which resulted in a discount on the New 2029 Notes of $3.9 million, inclusive of $0.3 million of fees paid to the Seller in the first quarter of 2020. The remaining $227 million of the exchange was executed in a series of transactions that were completed on April 8, 2020.

In addition to the aforementioned transactions, during the quarter ended March 31, 2020, we also repurchased from other parties on the open market $1.3 million of 7.625% notes due 2020, $29.1 million of the 7.875% notes due 2021, and $0.8 million of the 8.875% debentures due 2021 using availability under our ABL Credit Facility. We recorded a gain on debt extinguishment of $0.3 million, offset by approximately $0.3 million in unamortized debt issuance costs in the first quarter of 2020 on the repurchase of these notes.

On October 15, 2018, we entered into a $550.0 million senior secured term loan B (the “Term Loan”) pursuant to a credit agreement (the “Term Loan Credit Agreement”). The Term Loan is scheduled to mature on January 15, 2024, at which time the remaining outstanding balance under the Term Loan will be due and payable. Principal payments of $1.4 million are due quarterly. The Term Loan bears interest based on the London Interbank Offered Rate (LIBOR) plus a margin of 5% or a base rate plus a margin of 4%.

We entered into an $800.0 million senior secured asset-based revolving credit facility (the “ABL Credit Facility”) on September 29, 2017, pursuant to a credit agreement (the “ABL Credit Agreement”), which replaced our prior $800.0 million senior secured revolving credit facility dated September 30, 2016. The ABL Credit Facility is scheduled to mature on September 29, 2022, at which time all outstanding amounts under the ABL Credit Facility will be due and payable.

The amount available to be borrowed under the ABL Credit Facility is equal to the lesser of (a) $800.0 million and (b) a borrowing base formula based on the amount of accounts receivable, inventory, machinery, equipment and, if we were to so elect in the future subject to the satisfaction of certain conditions, fee-owned real estate of ours and our material domestic subsidiaries, subject to certain eligibility criteria and advance rates (collectively, the “Borrowing Base”). The aggregate amount of real estate, machinery and equipment that can be included in the Borrowing Base formula cannot exceed $200.0 million.

Borrowings under the ABL Credit Facility bear interest at a rate dependent on the average quarterly availability and is calculated according to a base rate (except in certain circumstances, based on the prime rate) or a Eurocurrency rate (except in certain circumstances, based on LIBOR) plus an applicable margin. The applicable margin for base rate loans ranges from 0.25% to 0.50% and the applicable margin for Eurocurrency loans ranges from 1.25% to 1.50%. In addition, a fee is payable quarterly on the unused portion of the total commitments. This fee accrues at a rate of either 0.25% or 0.375% depending upon the average usage of the facility. Borrowings under the ABL Credit Facility may be used for working capital and general corporate purposes.

During the first quarter of 2020, we increased our borrowings under the ABL Credit Facility to $450 million as a proactive measure in response to the COVID-19 pandemic. Based on our Borrowing Base as of March 31, 2020 and outstanding borrowings, we had approximately $192.9 million borrowing capacity available under the ABL Credit Facility. The weighted average interest rate on borrowings under our ABL Credit Facility was 2.7% and 3.9% during the three months ended March 31, 2020 and 2019, respectively.

The ABL Credit Agreement and Term Loan Credit Agreement contain customary affirmative and negative covenants including negative covenants restricting, among other things, our ability to incur debt, make investments, make certain restricted payments (including payments on certain other debt and external dividends), incur liens securing other debt, consummate certain fundamental transactions, enter into transactions with affiliates and consummate asset sales. The ABL Credit Agreement contains a covenant which requires us to maintain a minimum fixed charge coverage ratio of 1.0 to 1.0 if availability under the ABL Credit Facility declines below certain levels. The Term Loan Credit Agreement requires that the net cash proceeds of significant asset sales be used to prepay the Term Loan to the extent that the net cash proceeds are not used for reinvestment in assets useful to our business, certain acquisitions and investments, repayment of certain borrowings under our ABL Credit Facility or the funding of debt repayments, redemptions or tenders of certain existing notes maturing prior to the maturity of the Term Loan, in each case, subject to certain restrictions and limitations set forth in the Term Loan Credit Agreement.

Interest paid was $23.5 million for the three months ended March 31, 2020 and $38.6 million for the three months ended March 31, 2019.

Interest income was $0.5 million for the three months ended March 31, 2020 and $0.8 million for the three months ended March 31, 2019.