Derivative and Hedging Instruments - Effect of the Interest Rate Swap Agreements (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Results Recognized in Accumulated Other Comprehensive Income (Loss) (effective Portion)	$ 8,573	$ 0
Amount of gain or (loss) reclassified from accumulated other comprehensive income (loss) to earnings	1,284	0
Floorplan Interest Expense
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of gain or (loss) reclassified from accumulated other comprehensive income (loss) to earnings	716	0
Interest Expense
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of gain or (loss) reclassified from accumulated other comprehensive income (loss) to earnings	$ 568	$ 0