Debt - Overdraft Facilities (Details) - Sep. 30, 2023 € in Thousands, £ in Thousands, SFr in Thousands, $ in Thousands	GBP (£)	USD ($)	EUR (€)	CHF (SFr)
Haynes International Ltd. overdraft facility
Debt and long-term obligations
Maximum borrowing capacity	£ 1,333	$ 1,633
Available borrowing capacity	£ 1,333	1,633
Haynes International S.A.R.L. overdraft facility
Debt and long-term obligations
Maximum borrowing capacity		254	€ 240
Available borrowing capacity		254	€ 240
Haynes International AG overdraft facility
Debt and long-term obligations
Maximum borrowing capacity		1,315		SFr 1,200
Available borrowing capacity		$ 1,315		SFr 1,200