Pension Plans - Fair Value of Plan Assets (Details) - USD ($) $ in Thousands		Sep. 30, 2024	Sep. 30, 2023
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		$ 77,757	$ 68,875
Government
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		48,146	27,322
Equities in Funds
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		9,550
Corporate Investment Grade
Fair Value of Plan Assets [Line Items]
Fair value of plan assets			1,632
Large Capitalization Stocks
Fair Value of Plan Assets [Line Items]
Fair value of plan assets			20,864
Commodity Option
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		4,309	4,977
Insurance Company Funds
Fair Value of Plan Assets [Line Items]
Fair value of plan assets	[1]	7,385	7,102
Options
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		90
Cash
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		8,277	6,978
Level 1
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		70,372	61,773
Level 1 | Government
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		48,146	27,322
Level 1 | Equities in Funds
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		9,550
Level 1 | Corporate Investment Grade
Fair Value of Plan Assets [Line Items]
Fair value of plan assets			1,632
Level 1 | Large Capitalization Stocks
Fair Value of Plan Assets [Line Items]
Fair value of plan assets			20,864
Level 1 | Commodity Option
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		4,309	4,977
Level 1 | Insurance Company Funds
Fair Value of Plan Assets [Line Items]
Fair value of plan assets	[1]	0	0
Level 1 | Options
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		90
Level 1 | Cash
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		8,277	6,978
Level 2
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		7,385	7,102
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
Level 2 | Corporate Investment Grade
Fair Value of Plan Assets [Line Items]
Fair value of plan assets			0
Level 2 | Large Capitalization Stocks
Fair Value of Plan Assets [Line Items]
Fair value of plan assets			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]	7,385	7,102
Level 2 | Options
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		0
Level 2 | Cash
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
Level 3 | Corporate Investment Grade
Fair Value of Plan Assets [Line Items]
Fair value of plan assets			0
Level 3 | Large Capitalization Stocks
Fair Value of Plan Assets [Line Items]
Fair value of plan assets			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 | Options
Fair Value of Plan Assets [Line Items]
Fair value of plan assets		0
Level 3 | Cash
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.