Goodwill and Other Identifiable Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Goodwill [Abstract]
Net balance - beginning of period	$ 378,588
Acquisitions during the three months ended December 31, 2022	18,880
Net balance - end of period	397,468
Intangible Assets [Abstract]
Net balance - beginning of period	306,471
Acquisitions during the three months ended December 31, 2022	8,400
Accumulated amortization for the three months ended December 31, 2022	(3,292)	$ 0
Net balance - end of period	311,579
Expected Amortization Expense [Abstract]
2023 (excluding the three months ended December 31, 2022)	9,877
2024	13,170
2025	13,170
2026	13,170
2027	12,982
Thereafter	54,031
Finite-Lived Intangible Assets, Net	116,400
Dealerships [Member]
Goodwill [Abstract]
Net balance - beginning of period	280,000
Net balance - end of period	298,900
Distribution [Member]
Goodwill [Abstract]
Net balance - beginning of period	98,600
Net balance - end of period	98,600
Developed Technologies [Member]
Intangible Assets [Abstract]
Net balance - beginning of period	14,274
Acquisitions during the three months ended December 31, 2022	0
Accumulated amortization for the three months ended December 31, 2022	(386)
Net balance - end of period	13,888
Customer Relationships [Member]
Intangible Assets [Abstract]
Net balance - beginning of period	101,230
Acquisitions during the three months ended December 31, 2022	0
Accumulated amortization for the three months ended December 31, 2022	(2,687)
Net balance - end of period	98,543
Domain Names [Member]
Intangible Assets [Abstract]
Net balance - beginning of period	1,970
Acquisitions during the three months ended December 31, 2022	0
Accumulated amortization for the three months ended December 31, 2022	(104)
Net balance - end of period	1,866
Internally Developed Software [Member]
Intangible Assets [Abstract]
Net balance - beginning of period	2,218
Acquisitions during the three months ended December 31, 2022	0
Accumulated amortization for the three months ended December 31, 2022	(115)
Net balance - end of period	2,103
Trade Names [Member]
Intangible Assets [Abstract]
Net balance - beginning of period	186,779
Acquisitions during the three months ended December 31, 2022	8,400
Net balance - end of period	$ 195,179