Pension and Retirement Plans - Amounts in consolidated balance sheets (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Sep. 30, 2024
Pension and Retirement Plans
Pension benefits assets	$ 42	$ 2,201
Accrued benefit liability	(1,296)	(1,382)
Defined Benefit Plan, Net	(1,254)	819
Deferred tax	244	235
Accumulated other comprehensive income	2,885	80
Net amount recognized	1,875	1,134
Accumulated benefit obligation	(9,724)	(10,547)
Pension
Pension and Retirement Plans
Pension benefits assets		2,041
Accrued benefit liability	(89)
Deferred tax	23	23
Accumulated other comprehensive income	3,043	224
Net amount recognized	2,977	2,288
Accumulated benefit obligation	(8,559)	(9,325)
Post Retirement:
Pension and Retirement Plans
Accrued benefit liability	(1,165)	(1,222)
Deferred tax	221	212
Accumulated other comprehensive income	(158)	(144)
Net amount recognized	(1,102)	(1,154)
Accumulated benefit obligation	(1,165)	(1,222)
International
Pension and Retirement Plans
Pension benefits assets	42	2,201
Deferred tax	0	0
Accumulated other comprehensive income	3,031	212
Net amount recognized	3,073	2,413
Accumulated benefit obligation	(8,428)	(9,165)
International | Pension
Pension and Retirement Plans
Pension benefits assets	42	2,201
Deferred tax	0	0
Accumulated other comprehensive income	3,031	212
Net amount recognized	3,073	2,413
Accumulated benefit obligation	(8,428)	(9,165)
International | Post Retirement:
Pension and Retirement Plans
Accrued benefit liability	0	0
Deferred tax	0	0
Accumulated other comprehensive income	0	0
Net amount recognized	0	0
Accumulated benefit obligation	0	0
U.S.
Pension and Retirement Plans
Accrued benefit liability	(1,296)	(1,382)
Deferred tax	244	235
Accumulated other comprehensive income	(146)	(132)
Net amount recognized	(1,198)	(1,279)
Accumulated benefit obligation	(1,296)	(1,382)
U.S. | Pension
Pension and Retirement Plans
Accrued benefit liability	(131)	(160)
Deferred tax	23	23
Accumulated other comprehensive income	12	12
Net amount recognized	(96)	(125)
Accumulated benefit obligation	(131)	(160)
U.S. | Post Retirement:
Pension and Retirement Plans
Accrued benefit liability	(1,165)	(1,222)
Deferred tax	221	212
Accumulated other comprehensive income	(158)	(144)
Net amount recognized	(1,102)	(1,154)
Accumulated benefit obligation	$ (1,165)	$ (1,222)