Fair Value Measurements - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Interest expense - net	$ 470	$ 3,761	$ 4,911	$ 6,134
Swap
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Derivative, notional amount	$ 50,000	50,000
Investment income		$ 289	$ 114	$ 34

Nominal or face amount used to calculate payment on derivative.

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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.

+ References

No definition available.

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- Definition

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

+ References

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- Definition

Amount before accretion (amortization) of purchase discount (premium) of interest income on nonoperating securities.

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