Note 5 - Financing Arrangements - Long-term Debt (Details) (Parentheticals) - Real Estate Term Note [Member] $ in Millions	12 Months Ended
Dec. 31, 2020 USD ($)
Variable rate basis	2.25%
Interest rate	4.30%
Monthly payments	$ 41

Contractual interest rate for funds borrowed, under the debt agreement.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Amount of the required periodic payments including both interest and principal payments.

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The percentage points added to the reference rate to compute the variable rate on the interest rate derivative.

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