Interest Expense

6 Months Ended

Jun. 30, 2019

Interest and Debt Expense [Abstract]

The following tables present the components of interest expense:



	For the Three Months Ended June 30,				For the Six Months Ended June 30,
	2019		2018		2019		2018
	(Dollars in thousands)
Interest incurred on debt	$	31,389	$	22,554	$	63,509	$	35,473
Related-party Promissory Note interest expense	—		5,090		—		5,090
Senior Note redemption premium	—		—		—		4,782
Accretion of fair value adjustment on Senior Notes	—		—		—		19,414
Accretion of original issue discount on 2018 Term Loans	549		268		1,098		357
Amortization of debt issuance costs	1,031		755		2,062		1,416
Total interest expense	$	32,969	$	28,667	$	66,669	$	66,532

Interest Rates

The 2018 Credit Agreement had an effective interest rate of 5.90% as of June 30, 2019. The Old Revolving Facility and Old Term Loan Facility had an effective interest rate of 4.57% as of December 31, 2018 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 six months ended June 30, 2018 resulting from the prepayment. Amortization of debt issuance costs included $0.3 million of accelerated amortization related to the refinancing.