v3.26.1
Financial Instruments and Fair Value Measurements (Estimated Fair Values of Financial Instruments) (Details) - Level 2 [Member] - USD ($)
$ in Thousands
Jun. 30, 2026
Sep. 30, 2025
Liabilities:    
Long-term debt, Estimated Fair Value $ 734,915 $ 566,582
Long-term debt, Carrying Cost 750,014 580,547
Long Term Notes Receivable from Municipalities [Member]    
ASSETS    
Notes receivable, Estimated Fair Value 5,186 5,444
Liabilities:    
Notes receivable, Carrying Cost $ 5,105 $ 5,392