Note 10 - Employee Benefits (Details Textual)		12 Months Ended
	Dec. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay		100.00%
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent		4.00%
Participants in Employee Health Plan	2,274	2,274
Health Care Cap Per Person		$ 200,000
Insured Capped Maximum Exposure, Health Care		16,600,000
Employee Benefit Costs		15,728,000	$ 15,649,000
Other Labor-related Expenses		2,900,000	1,900,000
Insured Maximum Exposure Per Employee		1,000,000
Aggregate Insurance Deductible for Employees	$ 4,000,000
Operating Expense [Member]
Employee Benefit Costs		$ 15,200,000	$ 15,000,000.0