Long-Term Debt - Narrative (Details)	Sep. 27, 2019 USD ($)	Jun. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Oct. 31, 2001 USD ($)
Line Of Credit Facility [Line Items]
Revolving credit facility borrowings, outstanding amount		$ 800,000	$ 1,200,000
U.S. Revolver
Line Of Credit Facility [Line Items]
Percentage of voting capital stock pledged as collateral		100.00%
Non-domestic subsidiaries of voting capital stock		65.00%
U.S. Revolver | Amended and Restated Credit Agreement
Line Of Credit Facility [Line Items]
Revolving credit facility	$ 75,000,000.0
Revolving credit facility borrowings, outstanding amount		$ 0
Amount available under the credit facility		41,900,000
Debt covenant, consolidated leverage ratio (less than)	3.0
Debt covenant, consolidated interest coverage ratio (greater than)	3.0
Cash collateral pledged balance	$ 30,000,000
U.S. Revolver | Amended and Restated Credit Agreement | Fed Funds Rate
Line Of Credit Facility [Line Items]
Basis spread on variable rate	0.50%
U.S. Revolver | Amended and Restated Credit Agreement | LIBOR
Line Of Credit Facility [Line Items]
Basis spread on variable rate	1.00%
U.S. Revolver | Amended and Restated Credit Agreement | Base Rate | Minimum
Line Of Credit Facility [Line Items]
Basis spread on variable rate	(0.25%)
U.S. Revolver | Amended and Restated Credit Agreement | Base Rate | Maximum
Line Of Credit Facility [Line Items]
Basis spread on variable rate	1.75%
U.S. Revolver | Amended and Restated Credit Agreement | Financial Standby Letter of Credit
Line Of Credit Facility [Line Items]
Guarantee liability		33,100,000
Industrial Development Revenue Bonds
Line Of Credit Facility [Line Items]
Borrowings				$ 8,000,000.0
Reimbursement agreement requires annual redemptions		$ 400,000
Interest rate		0.36%