DEBT

A summary of long-term debt is as follows:



	September 30,
(In thousands)	2016		2015
Senior Notes 6.5% due 2020 ("Senior Notes")	$	447,919	$	648,268
Revolving Credit Facility	780,000		1,030,000
Total long-term debt	$	1,227,919	$	1,678,268

Senior Notes (Due February 2020)

As of September 30, 2016, $448.7 million aggregate principal amount of our Senior Notes were outstanding. Our Senior Notes are presented in the table above together with the unamortized premium from their issuance of $3.2 million and $5.9 million and net of unamortized debt issuance costs of $4.0 million and $7.4 million as of September 30, 2016 and September 30, 2015, respectively. Our Senior Notes are unsecured obligations and are not guaranteed by any of our subsidiaries.

Gains on extinguishment of debt

During the year ended September 30, 2016, we repurchased $201.4 million aggregate principal amount of our Senior Notes at an aggregate cost of $135.7 million, that included payment for accrued interest of $3.7 million. As a result of the repurchases, we recognized a total gain on debt retirement, net of the write-off of debt issuance costs and premium, of $69.0 million ($54.7 million net of tax, or $0.84 per diluted share) in Gains on extinguishment of debt on the Consolidated Statements of Operations for fiscal year 2016. The repurchases were made using available cash balances.

Revolving Credit Facility

As of September 30, 2016, our revolving credit facility (the "Credit Facility"), had total commitments of $1.395 billion through May 2018 and $1.120 billion through May 2019. Our wholly-owned subsidiary, Atwood Offshore Worldwide Limited (“AOWL”), is the borrower under the Credit Facility and we and certain of our other subsidiaries are guarantors under the facility.

On March 25, 2016, we entered into an amendment to our Credit Facility (the "Fourth Amendment") that, among other things, effective on March 28, 2016, (i) removed the maximum leverage ratio and maximum secured leverage ratio financial covenants, (ii) amended the minimum interest expense coverage ratio such that it is not applicable until the quarter ending September 30, 2018, and decreased the minimum ratio required to 1.15:1.00, (iii) added a minimum liquidity financial covenant of $150 million, (iv) revised the restricted payments covenant to prohibit us from paying dividends, (v) reduced the total commitments under the Credit Facility by $152 million, and (vi) permits the incurrence of up to $400 million of second lien debt, subject to the parameters set forth therein. As a result of the Fourth Amendment, borrowings under the Credit Facility bear interest at the Eurodollar rate plus a margin ranging from 2.50% to 3.25% and the commitment fee on the unused portion of the underlying commitment ranges from 1.00% to 1.30% per annum, in each case based on our corporate credit ratings.

The Credit Facility was secured primarily by first preferred mortgages on eight of our active drilling units prior to the Fourth Amendment (Atwood Aurora, Atwood Beacon, Atwood Condor, Atwood Eagle, Atwood Falcon, Atwood Mako, Atwood Manta and Atwood Osprey), as well as liens on the equity interests of our subsidiaries that own, directly or indirectly, such drilling units. In connection with the amendment, we mortgaged the Atwood Achiever, the Atwood Advantage and the Atwood Orca as additional collateral under the Credit Facility, as well as pledged the equity interests in our subsidiaries that own, directly or indirectly, these three vessels. Additionally, the Atwood Eagle and Atwood Falcon, along with the pledged equity interests in certain of our subsidiaries that, directly or indirectly, own these two vessels, were removed as collateral under the Credit Facility. Our interest in the two drillships under construction remain unencumbered by the Credit Facility.

As of September 30, 2016, our Credit Facility had $1.395 billion of total commitments and we had $780 million of outstanding borrowings. As of September 30, 2016, we had approximately $615 million available for borrowings under the Credit Facility. Approximately $275 million of the commitments mature in May 2018 and approximately $1.12 billion of the commitments under the Credit Facility mature in May 2019. We were in compliance with all financial covenants under the Credit Facility as of September 30, 2016 and 2015, and we anticipate that we will continue to be in compliance for the next fiscal year.

Letter of Credit Facility

On July 29, 2015, our subsidiary AOWL, entered into a letter of credit facility with BNP Paribas (“BNP”), pursuant to which BNP may, in its sole and absolute discretion, issue letters of credit from time to time at the request of AOWL, for the account of AOWL and its subsidiaries, up to an unlimited stated face amount of such letters of credit. Certain fees will be payable upon the issuance of each letter of credit under the letter of credit facility, with the amount of such fees depending on whether such letters of credit are performance letters of credit or financial letters of credit. BNP has no commitment under the facility to issue letters of credit, and the facility, as well as BNP’s willingness to receive requests from AOWL with respect to the issuance of letters of credit may be cancelled by BNP at any time. The facility contains certain events of default, including but not limited to delinquent payments, bankruptcy filings, material adverse judgments, cross-defaults under other debt agreements, or a change of control. As of September 30, 2016, we had no outstanding letters of credits under this facility.

Interest

The weighted-average effective interest rate on our long-term debt during fiscal years 2016 and 2015 was 4.94% and 2.60%, respectively. The effective rate was determined after giving consideration to the effect of our interest rate swaps accounted for as hedges and the amortization of premiums or discounts. Interest expense for fiscal years 2016, 2015 and 2014 was $68.6 million, $52.6 million and $41.8 million, respectively. Capitalized interest expense for fiscal 2016, 2015 and 2014 was $17.2 million, $22.2 million and $30.2 million, respectively.