Segment Information (Details) $ in Thousands	3 Months Ended
	Dec. 31, 2023 USD ($) segment	Dec. 31, 2022 USD ($)	Sep. 30, 2023 USD ($)
Segment Information [Abstract]
Number of reportable segments | segment	2
Revenue	$ 364,013	$ 366,659
Income (loss) from operations	6,471	26,536
Depreciation and amortization	4,905	6,182
Transaction costs	579	1,330
Change in fair value of contingent consideration	572	(1,409)
Total assets	1,693,073	1,672,093	$ 1,689,159
Eliminations
Segment Information [Abstract]
Revenue	(60)	0
Income (loss) from operations	(7)	0
Depreciation and amortization	0	0
Transaction costs	0	0
Change in fair value of contingent consideration	0	0
Total assets	(33)	0
Dealerships | Operating Segments
Segment Information [Abstract]
Revenue	331,607	326,773
Income (loss) from operations	6,943	29,853
Depreciation and amortization	2,902	2,375
Transaction costs	440	1,182
Change in fair value of contingent consideration	572	(1,543)
Total assets	1,445,553	1,283,821
Distribution | Operating Segments
Segment Information [Abstract]
Revenue	32,466	39,886
Income (loss) from operations	(465)	(3,317)
Depreciation and amortization	2,003	3,807
Transaction costs	139	148
Change in fair value of contingent consideration	0	134
Total assets	$ 247,553	$ 388,272