Debt - Interest (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Debt Disclosure [Abstract]
Accretion of debt discount	$ 3,816	$ 3,846	$ 8,496	$ 11,388
Interest on revolving credit facility	1,259	1,529	5,786	2,725
Coupon interest	1,951	2,264	4,962	6,792
Amortization of issuance costs	922	1,160	2,186	2,880
Undrawn and other fees	191	187	477	560
Total interest expense	$ 8,139	$ 8,986	$ 21,907	$ 24,345

Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense.

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Amount of amortization expense attributable to debt issuance costs.

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Amount of commitment fees for the unused borrowing capacity under the long-term financing arrangement that is available to the entity.

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

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Represents the portion of interest incurred in the period on debt arrangements that was charged against earnings, excluding amortization of debt discount (premium) and financing costs.

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

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