Long-Term Debt - Senior Notes Net Interest Expense (Details) - Senior Notes - 6.125% Senior Notes - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Interest Expense and Amortization of Debt Issue Costs
Interest expense	$ 8,702	$ 8,684	$ 26,092	$ 26,041
Debt issue cost amortization	321	321	963	961
Debt discount amortization	275	263	737	775
Total	$ 9,298	$ 9,268	$ 27,792	$ 27,777

Amount of amortization expense attributable to debt issuance costs.

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Represents the charge against earnings during the period for commitment fees and debt issuance expenses.

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Amount of the cost of borrowed funds accounted for as interest expense.

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Aggregate amount of interest paid or due on all long-term debt.

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