Financial Instruments and Fair Value Measurements (Narrative) (Details) $ in Thousands	Jan. 31, 2020	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Promissory note due date	Apr. 30, 2022
Measurement Input, Discount Rate [Member] | Long-Term Debt [Member] | Weighted Average [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Interest rate used to measure long-term debt		1.6	1.5
Long Term Notes Receivable from Municipalities [Member] | Measurement Input, Discount Rate [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Interest rate used to measure municipal notes		1.3	1.2
Interest rate used to measure promissory notes		1.0	2.3
Investments in Short-Term Time Deposits [Member] | Measurement Input, Discount Rate [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Interest rate used to measure short-term time deposits		3.3	4.4
Cross Currency Interest Rate Swaps [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Cross currency interest rate swaps		$ 50,185	$ 51,387