Debt (Interest) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Interest Expense, Debt [Abstract]
Total			$ 9,896	$ 5,630
Convertible Notes Credit And Amended And Restated Credit Agreements
Interest Expense, Debt [Abstract]
Accretion of debt discount	$ 3,784	$ 2,411	7,542	3,829
Coupon interest	2,264	1,366	4,528	2,121
Amortization of issuance costs	862	621	1,720	1,071
Interest on revolving credit facility	1,196	1,429	1,196	3,994
Undrawn and other fees	157	165	373	213
Total	$ 8,263	$ 5,992	$ 15,359	$ 11,228

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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