Goodwill and Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Goodwill [Abstract]
Net balance - beginning of period	$ 168,491	$ 113,059
Goodwill acquisitions during the year	210,097	55,432
Net balance - end of period	378,588	168,491	$ 113,059
Intangible Assets [Abstract]
Net balance - beginning of period	85,294	61,304
Acquisitions during the year	228,807	23,990
Accumulated amortization for the year	(7,630)	0	0
Net balance - end of period	306,471	85,294	61,304
Expected Amortization Expense [Abstract]
2023	13,170
2024	13,170
2025	13,170
2026	13,170
2027	12,951
Thereafter	54,061
Finite-Lived Intangible Assets, Net	119,692
Dealerships [Member]
Goodwill [Abstract]
Net balance - end of period	280,000
Distribution [Member]
Goodwill [Abstract]
Net balance - end of period	98,600
Developed Technologies [Member]
Intangible Assets [Abstract]
Net balance - beginning of period	0	0
Acquisitions during the year	15,457	0
Accumulated amortization for the year	(1,183)
Net balance - end of period	$ 14,274	0	0
Weighted average useful lives	10 years
Customer Relationships [Member]
Intangible Assets [Abstract]
Net balance - beginning of period	$ 0	0
Acquisitions during the year	107,490	0
Accumulated amortization for the year	(6,260)
Net balance - end of period	$ 101,230	0	0
Weighted average useful lives	10 years
Domain Names [Member]
Intangible Assets [Abstract]
Net balance - beginning of period	$ 0	0
Acquisitions during the year	2,074	0
Accumulated amortization for the year	(104)
Net balance - end of period	$ 1,970	0	0
Weighted average useful lives	5 years
Internally Developed Software [Member]
Intangible Assets [Abstract]
Net balance - beginning of period	$ 0	0
Acquisitions during the year	2,301	0
Accumulated amortization for the year	(83)
Net balance - end of period	$ 2,218	0	0
Weighted average useful lives	5 years
Trade Names [Member]
Intangible Assets [Abstract]
Net balance - beginning of period	$ 85,294	61,304
Acquisitions during the year	101,485	23,990
Net balance - end of period	$ 186,779	$ 85,294	$ 61,304

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Amount of increase in assets, excluding financial assets and goodwill, lacking physical substance with a definite life and an indefinite life, from an acquisition.

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Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of amortization for asset, excluding financial asset and goodwill, lacking physical substance with finite life expected to be recognized after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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