Note 10 - Federal Income Taxes - Consolidated Income Tax Expense (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Current expense	$ 12,675,000	$ 14,945,000	$ 10,978,000
Deferred expense	2,020,000	(4,141,000)	26,000
Change in valuation allowance	0	(94,000)	0
Tax expense	$ 14,695,000	$ 10,710,000	$ 11,004,000