Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Net sales	$ 112,454	$ 111,212
North America
Disaggregation of Revenue [Line Items]
Net sales	95,667	91,316
Europe
Disaggregation of Revenue [Line Items]
Net sales	16,787	19,896
Commercial revenue
Disaggregation of Revenue [Line Items]
Net sales	54,999	58,747
Military revenue
Disaggregation of Revenue [Line Items]
Net sales	57,455	52,465
Fixed wing aircraft
Disaggregation of Revenue [Line Items]
Net sales	52,895	56,891
Rotorcraft
Disaggregation of Revenue [Line Items]
Net sales	23,602	22,053
Energy components for power generation units
Disaggregation of Revenue [Line Items]
Net sales	17,646	20,893
Commercial product and other revenue
Disaggregation of Revenue [Line Items]
Net sales	$ 18,311	$ 11,375