Pension and Retirement Plans - Accrued benefit liability (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Sep. 30, 2021
Liability, Defined Benefit Plan [Abstract]
Non-current benefits assets	$ 1,099	$ 0
Current accrued benefit liability	110	308
Non-current accrued benefit liability	1,337	4,097
Total accrued benefit liability	1,447	4,405
Accumulated other comprehensive income	358	$ 4,218
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year	191
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year	$ 200