Revenue (Schedule of Contract Liability) (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Sep. 30, 2024
Contract With Customer Liability [Line Items]
Current contract liabilities	$ 48,290	$ 56,791
Noncurrent contract liabilities	431,235	424,609
Deferred Revenue from Material Rights from JV Formation [Member]
Contract With Customer Liability [Line Items]
Current contract liabilities	7,119	6,580
Noncurrent contract liabilities	232,173	232,164
Deferred Revenue From Advance Invoicing And/Or Prepayments From Customers [Member]
Contract With Customer Liability [Line Items]
Current contract liabilities	15,016	23,706
Noncurrent contract liabilities	4,678	6,437
Liability Related To Customer Supplied Inventory [Member]
Contract With Customer Liability [Line Items]
Current contract liabilities	17,247	20,563
Deferred Revenue From Material Rights Related To Engineering And Development Funding [Member]
Contract With Customer Liability [Line Items]
Current contract liabilities	8,908	5,942
Noncurrent contract liabilities	$ 194,384	$ 186,008