Note 1 - Summary of Significant Accounting Policies (Details Textual) - USD ($)	3 Months Ended	9 Months Ended
Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent			21.00%
Other Comprehensive Income (Loss) Taxes			$ 3,288,000	$ 486,000
Geographic Concentration Risk [Member] \| Revenue from Contract with Customer Benchmark [Member] \| ILLINOIS
Concentration Risk, Percentage	20.30%	22.10%	22.20%	23.90%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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