Note E - Marketable Securities and Time Deposits (Details Textual) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Total	$ 0
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	42,286
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	288
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0
Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-sale	46,924	$ 20,906
Proceeds from Sale of Debt Securities, Available-for-sale	24,553	$ 21,498
Debt Securities, Available-for-sale, Realized Gain (Loss), Total	$ 39

Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on 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 of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of realized gain (loss) on 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 of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position without allowance for credit loss.

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The amount of other than temporary impairment (OTTI) losses on equity securities, OTTI related to credit losses on debt securities, and OTTI losses on debt securities when the entity intends to sell the securities or it is more likely than not that the entity will be required to sell the securities before recovery of its amortized cost basis. Additionally, this item includes OTTI losses recognized during the period on investments accounted for under the cost method of accounting.

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Amount of cash inflow from maturity, prepayment and call 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 of cash inflow from sale 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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