5.Credit Agreement

In May 2013, we entered into a $500 million five-year, amended and restated revolving credit agreement (“2013 Credit Agreement”) with certain financial institutions and Citibank, N.A. as Administrative Agent. No principal payments were made against our revolving credit facility during the six months ended June 30, 2015. During the six months ended June 30, 2014, we made principal payments of $35.0 million. The $197.8 million principal balance of our revolving credit facility is due in May 2018.

The 2013 Credit Agreement provides for an initial $500 million revolving credit facility, and, under specified circumstances, the revolving credit facility can be increased or one or more incremental term loan facilities can be added, provided that the incremental credit facilities do not exceed in the aggregate the sum of (a) $75 million plus (b) an additional amount not less than $25 million, so long as our total secured leverage ratio, calculated giving pro forma effect to the requested incremental borrowing and other customary and appropriate pro forma adjustment events, including any permitted acquisitions, is no greater than 2.5:1.0. The amount available to borrow is based on certain borrowing base calculations found in our 2013 Credit Agreement. The 2013 Credit Agreement is collateralized by our assets.

The 2013 Credit Agreement contains certain customary representations and warranties, affirmative and negative covenants, and events of default. The 2013 Credit Agreement requires us to comply, on a quarterly basis, with certain principal financial covenants, including a maximum consolidated leverage ratio of 3.25:1.00 and a minimum interest coverage ratio of 3.00:1.00. As of June 30, 2015, we were in compliance with all of the terms of the 2013 Credit Agreement.

The interest rates applicable to the revolving credit facility are, at our option, either (a) the LIBOR multiplied by the statutory reserve rate plus an interest margin ranging from 1.50% to 2.25% based on our consolidated leverage ratio, or (b) a base rate (which is equal to the greatest of (a) Citibank’s prime rate, (b) the federal funds effective rate plus 0.50% and (c) the one-month LIBOR plus 1.00% plus an interest margin ranging from 0.50% to 1.25% based on our consolidated leverage ratio). The applicable interest rate was 2.02% at June 30, 2015. We pay an unused commitment fee on the revolving credit facility during the term of the 2013 Credit Agreement ranging from 0.375% to 0.50% per annum based on our consolidated leverage ratio.

Our obligations under the 2013 Credit Agreement may be accelerated upon the occurrence of an event of default, which includes customary events of default including, without limitation, payment defaults, failures to perform affirmative covenants, failure to refrain from actions or omissions prohibited by negative covenants, the inaccuracy of representations or warranties, cross-defaults, bankruptcy and insolvency related defaults, defaults relating to judgments, defaults due to certain ERISA related events and a change of control default.

The interest expense and the commitment fees on the unused portion of our revolving credit facility are as follows (in thousands):

	June 30,				June 30,
	Three months ended				Six months ended
	2015		2014		2015		2014
Interest expense	$	1,014	$	1,000	$	2,040	$	2,164
Commitment fees	$	376	$	376	$	748	$	704

At June 30, 2015 and December 31, 2014, the unamortized balance of deferred origination fees and debt issue costs were $5.9 million and $6.9 million, respectively. For the three months ended June 30, 2015 and 2014, we amortized $0.5 million of interest expense related to our deferred origination fees and debt issue costs in each of the respective periods. For the six months ended June 30, 2015 and 2014, we amortized $1.0 million of interest expense related to our deferred origination fees and debt issue costs in each of the respective periods.

Although we expect that operating cash flows will continue to be a primary source of liquidity for our operating needs, the revolving credit facility may be used for general corporate purposes, including acquisitions, if necessary.

As part of our contractual agreement with a customer, we have an outstanding irrevocable letter of credit for $3.0 million, which we established against the revolving credit facility. The letter of credit will expire on June 30, 2016.