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Note H - Employee Benefit Plans - Funded Pensions Assets by Assets Category (Details) - USD ($) $ in Thousands | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
--- | --- | --- | ---
Total plan assets |  | $ 129,348 | $ 118,092 |
Total plan assets, percentage |  | 100.00% | 100.00% |
Pension Plan [Member] |  |  |  |
Total plan assets |  | $ 129,348 | $ 118,092 | $ 107,862
Pension Plan [Member] | Fair Value, Inputs, Level 1 [Member] |  |  |  |
Total plan assets |  | 106,639 | 107,943 |
Pension Plan [Member] | Fair Value, Inputs, Level 2 [Member] |  |  |  |
Total plan assets |  | 7,574 | 4,242 |
Pension Plan [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |
Total plan assets |  |  |  |
Equity Securities [Member] |  |  |  |
Total plan assets |  | $ 79,906 | $ 68,563 |
Total plan assets, percentage |  | 62.00% | 58.00% |
Equity Securities [Member] | Pension Plan [Member] |  |  |  |
Total plan assets |  | $ 79,906 | $ 68,563 |
Equity Securities [Member] | Pension Plan [Member] | Fair Value, Inputs, Level 1 [Member] |  |  |  |
Total plan assets |  | 79,906 | 68,563 |
Equity Securities [Member] | Pension Plan [Member] | Fair Value, Inputs, Level 2 [Member] |  |  |  |
Total plan assets |  |  |  |
Equity Securities [Member] | Pension Plan [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |
Total plan assets |  |  |  |
Debt Securities [Member] |  |  |  |
Total plan assets |  | $ 34,307 | $ 43,622 |
Total plan assets, percentage |  | 26.00% | 37.00% |
Debt Securities [Member] | Pension Plan [Member] |  |  |  |
Total plan assets |  | $ 34,307 | $ 43,622 |
Debt Securities [Member] | Pension Plan [Member] | Fair Value, Inputs, Level 1 [Member] |  |  |  |
Total plan assets |  | 26,733 | 39,380 |
Debt Securities [Member] | Pension Plan [Member] | Fair Value, Inputs, Level 2 [Member] |  |  |  |
Total plan assets |  | 7,574 | 4,242 |
Debt Securities [Member] | Pension Plan [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |
Total plan assets |  |  |  |
Other than Securities Investment [Member] |  |  |  |
Total plan assets |  | $ 15,135 | $ 5,907 |
Total plan assets, percentage |  | 12.00% | 5.00% |
Investments Excluding Investments at NAV [Member] | Pension Plan [Member] |  |  |  |
Total plan assets |  | $ 114,213 | $ 112,185 |
Investments Excluding Investments at NAV [Member] | Pension Plan [Member] | Fair Value, Inputs, Level 1 [Member] |  |  |  |
Total plan assets |  | 106,639 | 107,943 |
Investments Excluding Investments at NAV [Member] | Pension Plan [Member] | Fair Value, Inputs, Level 2 [Member] |  |  |  |
Total plan assets |  | 7,574 | 4,242 |
Investments Excluding Investments at NAV [Member] | Pension Plan [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |
Total plan assets |  |  |  |
Investment at NAV [Member] | Pension Plan [Member] |  |  |  |
Total plan assets | [1] | 15,135 | 5,907 |
Investment at NAV [Member] | Pension Plan [Member] | Fair Value, Inputs, Level 1 [Member] |  |  |  |
Total plan assets | [1] |  |  |
Investment at NAV [Member] | Pension Plan [Member] | Fair Value, Inputs, Level 2 [Member] |  |  |  |
Total plan assets | [1] |  |  |
Investment at NAV [Member] | Pension Plan [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |
Total plan assets | [1] |  |  |
[1] | Investment valued at NAV are comprised of cash, cash equivalents, and short-term investments used to provide liquidity for the payment of benefits and other purposes. The commingled funds are valued at NAV based on the market value of the underlying investments, which are primarily government issued securities.

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