Accumulated Other Comprehensive Loss - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2019	Sep. 30, 2018
Equity [Abstract]
Amortization of net (gain) loss included in net periodic pension cost	$ 127	$ 151

Amount, after tax, of reclassification adjustment from accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan.

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