Debt

Our obligations under debt arrangements consisted of the following:



	June 30, 2018						December 31, 2017
	Principal		Unamortized Discount and Debt Issuance Costs ⁽¹⁾		Net Value		Principal		Unamortized Discount and Debt Issuance Costs ⁽¹⁾		Net Value
Senior secured credit facility	$	1,306,300	$	—	$	1,306,300	$	1,099,200	$	—	$	1,099,200
5.750% senior unsecured notes due February 2021	—		—		—		145,170		1,303		143,867
6.750% senior unsecured notes due August 2022	750,000		14,433		735,567		750,000		16,077		733,923
6.000% senior unsecured notes due May 2023	400,000		5,158		394,842		400,000		5,691		394,309
5.625% senior unsecured notes due June 2024	350,000		5,268		344,732		350,000		5,717		344,283
6.500% senior unsecured notes due October 2025	550,000		8,851		541,149		550,000		9,462		540,538
6.250% senior unsecured notes due May 2026	450,000		7,676		442,324		450,000		8,002		441,998
Total long-term debt	$	3,806,300	$	41,386	$	3,764,914	$	3,744,370	$	46,252	$	3,698,118


(1)	Unamortized debt issuance costs associated with our senior secured credit facility (included in Other Long Term Assets on the Unaudited Condensed Consolidated Balance Sheet) were $12.4 million and $14.1 million as of June 30, 2018 and December 31, 2017, respectively.

As of June 30, 2018, we were in compliance with the financial covenants contained in our credit agreement and senior unsecured notes indentures.

Senior Secured Credit Facility

The key terms for rates under our $1.7 billion senior secured credit facility, which are dependent on our leverage ratio (as defined in the credit agreement), are as follows:

•The applicable margin varies from 1.50% to 3.00% on Eurodollar borrowings and from 0.50% to 2.00% on alternate base rate borrowings.

•Letter of credit fees range from 1.50% to 3.00%

•The commitment fee on the unused committed amount will range from 0.25% to 0.50%.

•The accordion feature is $300.0 million, giving us the ability to expand the size of the facility to up to $2.0 billion for acquisitions or growth projects, subject to lender consent.

At June 30, 2018, we had $1.3 billion borrowed under our $1.7 billion credit facility, with $22.4 million of the borrowed amount designated as a loan under the inventory sublimit. Our credit agreement allows up to $100.0 million of the capacity to be used for letters of credit, of which $1.2 million was outstanding at June 30, 2018. Due to the revolving nature of loans under our credit facility, additional borrowings and periodic repayments and re-borrowings may be made until the maturity date. The total amount available for borrowings under our credit facility at June 30, 2018 was $392.5 million.

Senior Unsecured Note Issuances, Redemption, and Extinguishment

On December 11, 2017, we issued $450 million in aggregate principal amount of 6.25% senior unsecured notes due May 15, 2026 (the "2026 Notes"). Interest payments are due May 15 and November 15 of each year with the initial interest payment due May 15, 2018. Our 2026 Notes mature on May 15, 2026. That issuance generated proceeds of $441.8 million, net of issuance costs incurred. We used $204.8 million of the net proceeds to redeem the portion of the 5.75% senior unsecured notes due February 15, 2021 (the "2021 Notes") that were validly tendered and the remaining net proceeds to repay a portion of the borrowings outstanding under our revolving credit facility. On February 15, 2018, we redeemed our remaining 2021 Notes in full at a redemption price of 101.438% of the principal amount, plus accrued and unpaid interest up to, but not including, the redemption date. We incurred a total loss of approximately $3.3 million relating to the extinguishment of those notes (including the write-off of the related unamortized debt issuance costs),which is recorded as "Other expense, net" in our Consolidated Statements of Operations.