Note 5 - Fair Value Measurements (Details Textual) - USD ($) $ in Thousands	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020
Long-term Debt, Fair Value	$ 112,500		$ 118,400
Long-term Debt, Gross	112,000		115,600
Fair Value, Nonrecurring [Member]
Assets, Fair Value Disclosure	0		0
Foreign Exchange Forward [Member] \| Maximum [Member]
Derivative Asset, Total		$ 100
Investments Held in Rabbi Trust [Member]
Debt Securities, Available-for-sale, Total	$ 400		$ 700

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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