Debt

Our notes payable are summarized as follows (in thousands):



	June 30, 2015		December 31, 2014
7.50% Senior Convertible Notes due 2016	46,793		55,481
7.50% Senior Exchange Convertible Notes due 2016	8,546		44,475
8.50% Senior Notes due 2019	200,000		200,000
6.00% Senior Convertible Notes due 2020, net of discount	79,872		—
Senior Secured Credit Facility	—		—
Total	$	335,211	$	299,956

We made interest payments of $9.7 million and $22.0 million for the three and six months ended June 30, 2015, respectively. We made interest payments of $0.1 million and $3.9 million for the three and six months ended June 30, 2014, respectively. We were in compliance with all debt covenants as of June 30, 2015 and December 31, 2014.

7.50% Senior Convertible Notes due 2016

On February 4, 2011, we completed an underwritten public offering for $100.0 million aggregate principal amount of our 7.50% Senior Convertible Notes due 2016 (the “7.50% Notes”). The 7.50% Notes mature on February 15, 2016 unless earlier converted, redeemed or repurchased. The 7.50% Notes are governed by the Indenture and the First Supplemental Indenture, each dated February 4, 2011, between us and the trustee named therein. Interest on the 7.50% Notes is payable semi-annually in arrears in cash on February 15 and August 15 of each year.

7.50% Senior Exchange Convertible Notes due 2016

In July 2012, we entered into exchange agreements under which we retired $44.5 million in aggregate principal amount of our 7.50% Notes, in exchange for the issuance of $44.5 million in aggregate principal of new 7.50% Senior Exchange Convertible Notes due 2016 (“7.50% Exchange Notes”). The 7.50% Exchange Notes mature on February 15, 2016 unless earlier converted, redeemed or repurchased. Effective as of February 15, 2015, we may, at our option, redeem for cash all or any portion of the 7.50% Exchange Notes prior to maturity at a redemption price equal to 100% of the principal amount, plus accrued and unpaid interest. The 7.50% Exchange Notes are governed by the Indenture dated February 4, 2011 and the Second Supplemental Indenture dated July 25, 2012 between us and the trustee named therein. Interest on the 7.50% Exchange Notes is payable semi-annually in arrears in cash on February 15 and August 15 of each year, commencing February 15, 2013.

8.50% Senior Notes due 2019

On June 30, 2014, we completed an underwritten offering for $200.0 million aggregate principal amount of our 8.50% Senior Notes due 2019 (the “8.50% Notes”). The 8.50% Notes mature on July 1, 2019 unless earlier converted, redeemed or repurchased. Interest on the 8.50% Notes is 8.50% per year, payable semi-annually in arrears in cash on January 1 and July 1 of each year, commencing January 1, 2015. The 8.50% Notes will be redeemable at our option, in whole or in part, at any time on or after July 1, 2016, at certain redemption prices, together with accrued and unpaid interest, if any, to, but excluding, the date of redemption.

6.00% Senior Convertible Notes due 2020

On June 23, 2015, we completed a private offering of $80.0 million aggregate principal amount of 6.00% Senior Convertible Notes due 2020 (the “6.00% Notes”). The 6.00% Notes were issued in exchange for $15.4 million aggregate principal amount of 7.50% Exchange Notes and $64.5 million in cash. We used $30.7 million of the net cash proceeds from the sale of the 6.00% Notes to (i) repurchase an additional $20.5 million aggregate principal amount of 7.50% Exchange Notes, (ii) repurchase $8.7 million aggregate principal amount of outstanding 7.50% Notes, and (iii) pay approximately $1.5 million of accrued interest (in respect of the notes being exchanged or repurchased) and premium (in respect of the notes being repurchased). The 6.00% Notes will mature on July 1, 2020, unless earlier repurchased or converted. The 6.00% Notes are governed by the Indenture dated February 4, 2011 and the Third Supplemental Indenture dated June 23, 2015 between us and the trustee named therein. The 6.00% Notes bear regular cash interest on the principal amount of each note, payable semiannually in arrears on January 1 and July 1 of each year, beginning on January 1, 2016.

The 6.00% Notes were issued pursuant a series of separate, privately negotiated note purchase agreements (the “Note Purchase Agreements”) entered into on June 17, 2015 by us and certain qualified institutional buyers. TPG Aviator, L.P. (“TPG”), which owns approximately 41% of our outstanding common stock, purchased $20.0 million aggregate principal amount of 6.00% Notes for $20.0 million in cash and waived its rights to purchase additional 6.00% Notes. Pursuant to the terms of the Company’s Related Person Transaction Policy, the audit committee of the Company’s board of directors reviewed and approved the terms of the 6.00% Notes and TPG’s purchase of 6.00% Notes.

Senior Secured Credit Facility

On April 7, 2014, we entered into a $65.0 million senior secured credit facility with JPMorgan Chase Bank, N.A., as agent, a lender and a letter of credit issuer (the "Senior Secured Credit Facility"). The other lenders and letter of credit issuers include Royal Bank of Canada and Credit Suisse AG. Later in 2014, we increased the senior secured credit facility by $40.0 million with the addition of Citibank, N.A., and Deutsche Bank, A.G., as additional lenders.

The Senior Secured Credit Facility includes revolving credit and letter of credit facilities in an aggregate principal amount of up to $105.0 million, with an “accordion” feature that allows us, with the consent of the lenders, to increase the aggregate amount to $175.0 million. The Senior Secured Credit Facility also includes a swing line loan facility in an aggregate principal amount of up to $30.0 million. At June 30, 2015, we had sufficient qualified assets in the borrowing base to cover the full capacity and had no borrowings outstanding. Subsequent to June 30, 2015, we drew $40.0 million on the Senior Secured Credit Facility.