Revenues from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Revenue from Contracts with Customers
Net revenues	$ 490,461	$ 337,661	$ 380,530
Product
Revenue from Contracts with Customers
Net revenues	467,250	316,081	356,825
Aerospace
Revenue from Contracts with Customers
Net revenues	230,001	128,072	191,980
Chemical processing
Revenue from Contracts with Customers
Net revenues	91,665	63,147	63,170
Industrial gas turbine
Revenue from Contracts with Customers
Net revenues	91,878	66,772	56,576
Other markets
Revenue from Contracts with Customers
Net revenues	53,706	58,090	45,099
Others
Revenue from Contracts with Customers
Net revenues	$ 23,211	$ 21,580	$ 23,705