Note 8 - Employee Benefit Plans (Details Textual)	3 Months Ended
	Dec. 31, 2022
Supplemental Employee Retirement Plan [Member]
Supplemental Retirement Benefit Period (Year)	15 years
Defined Benefit Plan Percent of Highest Average Salary Base	50.00%
Defined Benefit Plan Number of Years in Average Annual Base Salary (Year)	5 years
Defined Benefit Plan Number of Years Preceding Retirement for Average Annual Base Salary Calculation (Year)	10 years
Supplemental Employee Retirement Plan [Member] | Minimum [Member]
Defined Benefit Plan, Employment Term (Year)	30 years
Reduced SERP [Member]
Defined Benefit Plan Retirement Age	65
Defined Benefit Plan, Reduction for Each Month	0.28%
Reduced SERP [Member] | Minimum [Member]
Defined Benefit Plan, Employment Term (Year)	10 years