Pension and Retirement Plans - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2025	Sep. 30, 2024
Pension and Retirement Plans
Number of years defined benefit plans are closed to newly hired employees	2 years
Number of years supplementary retirement plans are closed to newly hired employees	2 years
Life insurance amount due	$ 1,296	$ 1,382
Pension
Pension and Retirement Plans
Life insurance amount due	$ 89
Individuals below 65 years
Pension and Retirement Plans
Defined benefit plan, health care cost trend rate	8.00%
Defined benefit plan, increase in health care cost trend rate	0.50%
Defined benefit plan, health care cost trend in 65 years	4.54%
Individuals at and above 65 years
Pension and Retirement Plans
Defined benefit plan, increase in health care cost trend rate	5.00%
Defined benefit plan, assumed health care cost rate, next fiscal year	4.75%
Defined benefit plan, assumed health care cost rate, thereafter	4.54%
U.S.
Pension and Retirement Plans
Life insurance amount due	$ 1,296	1,382
U.S. \| Pension
Pension and Retirement Plans
Loans, Gross, Insurance Policy	4,000	3,800
Life insurance amount due	$ 131	$ 160

Decrease in Ultimate increase trend rate for health care cost for defined benefit postretirement plan every year.

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- Definition

Assumed rate, for periods after next fiscal year, based on annual change in cost of health care cost benefits used to measure expected cost of benefits covered by defined benefit postretirement plan. Factors include, but are not limited to, estimate of health care inflation, change in health care utilization or delivery pattern, technological advances, and change in health status of participant. Excludes factors for change in composition of plan population by age and dependency status.

+ References

No definition available.

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- Definition

Ultimate health care cost trend for defined benefit postretirement plan in 65 years.

+ References

No definition available.

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- Definition

Number of years that all of the Company's defined benefit plans are closed to newly hired employees.

+ References

No definition available.

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- Definition

Number of years that the Company's supplementary retirement plans are closed to newly hired employees.

+ References

No definition available.

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- Definition

Assumed rate, for next fiscal year, based on annual change in cost of health care cost benefits used to measure expected cost of benefits covered by defined benefit postretirement plan. Factors include, but are not limited to, estimate of health care inflation, change in health care utilization or delivery pattern, technological advances, and change in health status of participant. Excludes factors for change in composition of plan population by age and dependency status.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
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-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (l)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-1

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- Definition

Ultimate trend rate for health care cost for defined benefit postretirement plan.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Amount before allowance of loans made to policy and contract holders using their life insurance contracts' cash value or separate accounts as collateral. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums over and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
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- Definition

Amount of liability, recognized in statement of financial position, for defined benefit pension and other postretirement plans.

+ References

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-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
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