Capital Leases - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Property, Plant and Equipment, Net	$ 161,470	$ 134,954
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	129,870	$ 115,728
Property, equipment and machinery under capital lease
Property, Plant and Equipment, Net	28,400
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	$ 3,500
Doble facility lease
Lease Expiration Date	2036
NRG and Mayday facility
Lease Expiration Date	2029,
Machinery
Lease Expiration Date	2020