Note 8 - Employee Benefit Plans (Details Textual)	3 Months Ended
	Dec. 31, 2016
Supplemental Employee Retirement Plan [Member]
Supplemental Retirement Benefit Period	15 years
Defined Benefit Plan Percent of Highest Average Salary Base	50.00%
Defined Benefit Plan Number of Years in Average Annual Base Salary	5 years
Defined Benefit Plan Number of Years Preceding Retirement for Average Annual Base Salary Calculation	10 years
Reduced SERP [Member]
Defined Benefit Plan Retirement Age	65
Defined Benefit Plan, Reduction for Each Month	0.0028%
Minimum [Member] | Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan Employment Term	30 years
Minimum [Member] | Reduced SERP [Member]
Defined Benefit Plan Employment Term	10 years