Employee Benefits Plans - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Retirement Benefits [Abstract]
Benefit plan period	180 months
Weighted-average discount rate	4.08%	4.30%
Estimated future benefit payments, year 2018	$ 348
Estimated future benefit payments, year 2019	357
Estimated future benefit payments, year 2020	160
Estimated future benefit payments, year 2021	192
Estimated future benefit payments, year 2022	192
Estimated future benefit payments, thereafter	$ 1,249