Amount of amortization expense attributable to debt issuance costs.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount, after accumulated amortization, of debt issuance costs classified as noncurrent. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Weighted average interest rate of long-term debt outstanding calculated at point in time.

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Debt - Deferred Financing Costs (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Mar. 05, 2018
Debt Instrument [Line Items]
Deferred financing costs related to convertible notes				$ 2,800
Amortization expenses of deferred financing costs included in Interest expense	$ 1,900	$ 1,800	$ 1,900
2018 Credit Agreement
Debt Instrument [Line Items]
Deferred financing costs related to convertible notes	1,200
Senior Convertible Notes 2016
Debt Instrument [Line Items]
Deferred financing costs related to convertible notes	$ 1,170	$ 2,334
Credit Agreement and Convertible Notes \| Debt Offerings
Debt Instrument [Line Items]
Weighted-average interest rate on debt borrowings	5.00%	6.00%	5.00%