Note H - Employee Benefit Plans - Weighted-average Assumptions Used for Measurement of Defined Pension Plans (Details)	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Qualified Plan I [Member]
Weighted-average assumptions used to determine net periodic benefit cost	3.20%	4.35%
Expected return on plan assets	4.75%	4.25%
Weighted-average assumptions used to determine benefit obligations, discount rate	2.37%	3.20%
Qualified Plan II [Member]
Weighted-average assumptions used to determine benefit obligations, discount rate	2.61%
Restoration Plan [Member]
Weighted-average assumptions used to determine net periodic benefit cost	3.14%	4.30%
Weighted-average assumptions used to determine benefit obligations, discount rate	2.34%	3.14%

Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan.

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- Definition

Weighted average rate for present value of future retirement benefits cash flows, used to determine net periodic benefit cost of defined benefit plan.

+ References

+ Details

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- Definition

Weighted average rate of return on plan assets, reflecting average rate of earnings expected on existing plan assets and expected contributions, used to determine net periodic benefit cost of defined benefit plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(3)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e2919-114920

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- Details

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