Retirement Plans - SERP and Directors’ Retirement plans, Change in Status (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning of year	$ 1,046	$ 1,062
Service cost	0	0
Interest cost	0	44
Curtailment and settlement	0	0
Actuarial loss (gain)	0	18
Benefits paid	(1,046)	(78)
End of year	0	1,046
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, beginning of year	0	0
Actual return on plan assets	0	0
Company contributions	0	78
Benefits paid	0	(78)
Plan assets at fair value, end of year	$ 0	$ 0