Pension Plans - Fair Value of Plan Assets (Details) - USD ($) $ in Thousands		Sep. 30, 2025	Sep. 30, 2024
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		$ 83,774	$ 77,757
Government
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		47,554	48,146
Equities in Funds
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		15,709	9,550
Commodity Option
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		5,077	4,309
Insurance Company Funds
Fair Value of Plan Assets [Line Items]
Fair value of plan assets	[1]	6,867	7,385
Cash
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		8,538	8,277
Options
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		29	90
Level 1
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		76,907	70,372
Level 1 | Government
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		47,554	48,146
Level 1 | Equities in Funds
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		15,709	9,550
Level 1 | Commodity Option
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		5,077	4,309
Level 1 | Insurance Company Funds
Fair Value of Plan Assets [Line Items]
Fair value of plan assets	[1]	0	0
Level 1 | Cash
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		8,538	8,277
Level 1 | Options
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		29	90
Level 2
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		6,867	7,385
Level 2 | Government
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		0	0
Level 2 | Equities in Funds
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		0	0
Level 2 | Commodity Option
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		0	0
Level 2 | Insurance Company Funds
Fair Value of Plan Assets [Line Items]
Fair value of plan assets	[1]	6,867	7,385
Level 2 | Cash
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		0	0
Level 2 | Options
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		0	0
Level 3
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		0	0
Level 3 | Government
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		0	0
Level 3 | Equities in Funds
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		0	0
Level 3 | Commodity Option
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		0	0
Level 3 | Insurance Company Funds
Fair Value of Plan Assets [Line Items]
Fair value of plan assets	[1]	0	0
Level 3 | Cash
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		0	0
Level 3 | Options
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		$ 0	$ 0

[1] These investments are comprised primarily of funds invested with an insurance company in Japan with a guaranteed rate of return. The insurance company invests these assets primarily in government and corporate bonds.