Derivative and Hedging Instruments - Effect of the Interest Rate Swap Agreements (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Results Recognized in Accumulated Other Comprehensive Income (Loss) (effective Portion)	$ (1,188)	$ 0	$ 4,463	$ 0
Amount of gain (loss) reclassified from accumulated other comprehensive income (loss) to earnings	814	0	2,952	0
Floorplan Interest Expense
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of gain (loss) reclassified from accumulated other comprehensive income (loss) to earnings	406	0	1,557	0
Interest Expense
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of gain (loss) reclassified from accumulated other comprehensive income (loss) to earnings	$ 408	$ 0	$ 1,395	$ 0