Note 6 - Employee Benefit Plans (Details Textual) - USD ($)	2 Months Ended	12 Months Ended
	Feb. 17, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets		6.40%	6.45%
Defined Benefit Plan Assumed Long Term Rate Basis Spread		1.00%
Defined Benefit Plan, Plan Assets, Contributions by Employer		$ 22,250,000	$ 23,731,000
Defined Contribution Plan, Employer Matching Contribution, Percent of Match		55.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay		5.00%
Defined Contribution Plan, Employer Discretionary Contribution Amount		$ 500,000	10,000	$ 10,000
Capital Accumulation 401(K) Plan [Member]
Defined Benefit Plan, Plan Assets, Contributions by Employer		$ 4,300,000	4,600,000	3,900,000
Defined Contribution Plan, Employer Matching Contribution, Percent of Match		100.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay		6.00%
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan, Plan Assets, Contributions by Employer		$ 16,800,000
Defined Benefit Plan, Expected Future Employer Contributions, Current Fiscal Year		5,500,000
Nonoperating Income (Expense) [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Except Service cost		$ 600,000	$ 2,900,000	$ 5,000,000.0
Subsequent Event [Member]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets	7.25%