Note 2 - Investments - Mortgage Loans by Loan-to-value Ratio (Details) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Total commercial mortgages	$ 3,775,432	$ 3,166,136
Debt-to-Value Ratio, 60 to 70 Percent [Member]
Total commercial mortgages	2,003,705	1,874,445
Debt-to-Value Ratio, 40 to 50 Percent [Member]
Total commercial mortgages	340,667	0
Debt-to-Value Ratio, 30 to 40 Percent [Member]
Total commercial mortgages	195,310	177,984
Debt-to-Value Ration, 10 to 30 Percent [Member]
Total commercial mortgages	$ 1,235,750	$ 1,113,707