Note H - Employee Benefit Plans - Acceptable Level of Volatility (Details)	Dec. 31, 2020
Other Pension Plan [Member] | Defined Benefit Plan, Equity Securities [Member]
Target rate	64.00%
Other Pension Plan [Member] | Defined Benefit Plan, Equity Securities [Member] | Minimum [Member]
Target rate	54.00%
Other Pension Plan [Member] | Defined Benefit Plan, Equity Securities [Member] | Maximum [Member]
Target rate	74.00%
Other Pension Plan [Member] | Defined Benefit Plan, Equity Securities, US, Large Cap [Member]
Target rate	23.00%
Other Pension Plan [Member] | Defined Benefit Plan, Equity Securities, US, Large Cap [Member] | Minimum [Member]
Target rate	18.00%
Other Pension Plan [Member] | Defined Benefit Plan, Equity Securities, US, Large Cap [Member] | Maximum [Member]
Target rate	28.00%
Other Pension Plan [Member] | Defined Benefit Plan, Equity Securities, US, Mid Cap [Member]
Target rate	15.00%
Other Pension Plan [Member] | Defined Benefit Plan, Equity Securities, US, Mid Cap [Member] | Minimum [Member]
Target rate	10.00%
Other Pension Plan [Member] | Defined Benefit Plan, Equity Securities, US, Mid Cap [Member] | Maximum [Member]
Target rate	20.00%
Other Pension Plan [Member] | Defined Benefit Plan, Equity Securities, US, Small Cap [Member]
Target rate	8.00%
Other Pension Plan [Member] | Defined Benefit Plan, Equity Securities, US, Small Cap [Member] | Minimum [Member]
Target rate	4.00%
Other Pension Plan [Member] | Defined Benefit Plan, Equity Securities, US, Small Cap [Member] | Maximum [Member]
Target rate	12.00%
Other Pension Plan [Member] | Defined Benefit Plan, Equity Securities, Non-US [Member]
Target rate	13.00%
Other Pension Plan [Member] | Defined Benefit Plan, Equity Securities, Non-US [Member] | Minimum [Member]
Target rate	8.00%
Other Pension Plan [Member] | Defined Benefit Plan, Equity Securities, Non-US [Member] | Maximum [Member]
Target rate	25.00%
Other Pension Plan [Member] | Defined Benefit Plan, Equity Securities, Emerging Markets [Member]
Target rate	5.00%
Other Pension Plan [Member] | Defined Benefit Plan, Equity Securities, Emerging Markets [Member] | Minimum [Member]
Target rate	0.00%
Other Pension Plan [Member] | Defined Benefit Plan, Equity Securities, Emerging Markets [Member] | Maximum [Member]
Target rate	8.00%
Pension Plan [Member] | Emerging Markets [Member]
Target rate	34.00%
Pension Plan [Member] | Emerging Markets [Member] | Minimum [Member]
Target rate	24.00%
Pension Plan [Member] | Emerging Markets [Member] | Maximum [Member]
Target rate	44.00%
Pension Plan [Member] | Investment Grade [Member]
Target rate	34.00%
Pension Plan [Member] | Investment Grade [Member] | Minimum [Member]
Target rate	24.00%
Pension Plan [Member] | Investment Grade [Member] | Maximum [Member]
Target rate	44.00%
Pension Plan [Member] | Cash Equivalent [Member]
Target rate	2.00%
Pension Plan [Member] | Cash Equivalent [Member] | Minimum [Member]
Target rate	0.00%
Pension Plan [Member] | Cash Equivalent [Member] | Maximum [Member]
Target rate	40.00%