8. Debt

Debt consists of the following (in thousands):


	June 30,		December 31,
	2016		2015
2013 Senior Secured Credit Facility, principal of $487 payable quarterly, matures in July 2020	$	188,902	$	202,635
Less unamortized debt issuance costs		(1,285)		(1,527)
Less unamortized debt discount costs		(634)		(751)
Less current portion		(10,765)		(14,805)
	$	176,218	$	185,552

Maturities of debt are as follows (in thousands):


As of June 30:
Remainder of 2016	$	974
2017		10,765
2018		1,947
2019		1,947
2020		173,269
	$	188,902

On July 31, 2013, the Company entered into a new credit agreement with several lenders and administered by a bank, referred to herein as the “2013 Senior Secured Credit Facility.” The 2013 Senior Secured Credit Facility consists of a $230,000,000 term loan facility and a $10,000,000 revolving loan facility. The proceeds provided by the term loan facility were used to refinance and repay existing indebtedness and for working capital, capital expenditures and general corporate purposes.

On March 11, 2015, the 2013 Senior Secured Credit Facility was amended, providing for an increase to the maximum applicable margin for both London Interbank Offered Rate (“LIBOR”) and Alternate Base Rate (“ABR”) loans by 0.25%, and a modification of certain liquidity covenants in order to increase the amounts the Company may distribute in the form of dividends to its non-controlling unitholders and stockholders of its Class A common stock, referred to herein as the “First Amendment.” Interest rates with respect to the amended term loan facility and revolving loan facility are based, at the Company’s option, on (a) adjusted LIBOR, provided that LIBOR shall be no less than 1% plus a maximum applicable margin of 3.25% or (b) ABR, provided that ABR shall be no less than 2%, which is equal to the greater of (1) JPMorgan Chase Bank, N.A.’s prime rate; (2) the Federal Funds Effective Rate plus 0.5% or (3) calculated Eurodollar Rate for a one month interest period plus 1%, plus a maximum applicable margin of 2.25%. The applicable margin is subject to quarterly adjustments based on the Company’s total leverage ratio as defined in the 2013 Senior Secured Credit Facility. In connection with the First Amendment, the Company incurred costs of $1,086,000 during the six months ended June 30, 2015 of which $555,000 was recorded as an unamortized debt discount and are being amortized over the remaining term of the 2013 Senior Secured Credit Facility and the remaining $531,000 was expensed as incurred.

The Company is required to make principal payments out of excess cash flow, as defined in the 2013 Senior Secured Credit Facility, as well as from the proceeds of certain asset sales, proceeds from the issuance of indebtedness and from insurance recoveries. The Company made an excess cash flow prepayment of $12,727,000 on March 31, 2016. As of June 30, 2016, mandatory principal payments of approximately $487,000 are due quarterly until the facility matures on July 31, 2020 and will be reduced pro-rata by the amount of any excess cash flow principal prepayments made. During the six months ended June 30, 2015, the Company made an excess cash flow prepayment of $7,320,000. The Company accounted for the mandatory principal excess cash flow prepayments as early extinguishments of debt and recorded a loss of $136,000 and $94,000 during the six months ended June 30, 2016 and 2015, respectively, related to unamortized debt discount and issuance costs. The Company may make optional prepayments on the term loan facility at any time; however, no such optional prepayments were made during the six months ended June 30, 2016 or 2015.

The estimated fair value of the Company’s debt as of June 30, 2016 and December 31, 2015 represents the amount that would be paid to transfer or redeem the debt in an orderly transaction between market participants at those dates and maximizes the use of observable inputs. The fair value of the Company’s debt was estimated using a market approach based on the amount at the measurement date that the Company would pay to enter into the identical liability, since quoted prices for the Company’s debt instruments are not available. As a result, the Company has classified the fair value of the 2013 Senior Secured Credit Facility as Level 2 of the fair value hierarchy. The carrying amounts of the 2013 Senior Secured Credit Facility are included in the accompanying Condensed Consolidated Balance Sheets in “Current portion of debt” and “Debt, net of current portion.” The following table summarizes the carrying value and fair value of the 2013 Senior Secured Credit Facility as of June 30, 2016 and December 31, 2015 (in thousands):


	June 30,				December 31,
	2016				2015
	Carrying Amounts		Estimated Fair Value		Carrying Amounts		Estimated Fair Value
2013 Senior Secured Credit Facility	$	186,983	$	188,902	$	200,357	$	198,583

The Company had no borrowings drawn on the revolving loan facility during the six months ended June 30, 2016 and 2015 and had $10,000,000 available under the revolving loan facility as of June 30, 2016. The Company must pay a quarterly commitment fee equal to 0.5% on the average daily amount of the unused portion of the revolving loan facility.