Interest Expense

9 Months Ended

Sep. 30, 2018

Interest and Debt Expense [Abstract]

Interest Expense

Interest Expense

The following tables present the components of interest expense: 

	For the Three Months Ended September 30,				For the Nine Months Ended September 30,
	2018		2017		2018		2017
	(Dollars in thousands)
Interest incurred on debt	$	32,278	$	6,097	$	67,751	$	18,183
Related party Promissory Note interest expense	—		—		5,090		—
Senior Note redemption premium	—		—		4,782		—
Accretion of fair value adjustment on Senior Notes	—		1,618		19,414		4,826
Accretion of original issue discount on 2018 Term Loans	549		—		906		—
Amortization of debt issuance costs	1,028		77		2,444		231
Total interest expense	$	33,855	$	7,792	$	100,387	$	23,240

Interest Rates

The 2018 Credit Agreement had an effective interest rate of 5.74% as of September 30, 2018. The Old Revolving Facility and Old Term Loan Facility had an effective interest rate of 4.57% as of December 31, 2017 and the Senior Notes had a fixed interest rate of 6.375%, both of which were repaid on February 12, 2018 as part of our refinancing (see Note 6 "Debt and Liquidity").

As a result of our February 12, 2018 refinancing, we paid a prepayment premium for the redemption of our Senior Notes totaling $4.8 million. The accretion of the August 15, 2015 fair value adjustment to our Senior Notes totaling $19.4 million included accelerated accretion of $18.7 million for the nine months ended September 30, 2018 resulting from the prepayment. Amortization of debt issuance costs included $0.3 million of accelerated amortization related to the refinancing.