CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities
Net income	$ 65,840	$ 42,367
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation and amortization	6,541	2,341
Equity-based awards	4,813	2,205
Gain on asset disposals	(14)	(136)
Non-cash interest expense	626	393
Deferred income tax provision	3,463	1,787
Loss on change in fair value of contingent consideration	7,904	0
(Increase) decrease in assets:
Accounts receivable	(44,119)	(22,417)
Inventories	(113,879)	(30,551)
Prepaid expenses and other current assets	(14,189)	1,083
Deposits	(50)	(128)
Increase (decrease) in liabilities:
Accounts payable	26,363	12,971
Other payables and accrued expenses	4,810	(126)
Tax receivable agreement liability	313	0
Customer deposits	8,156	20,792
Net cash (used in) provided by operating activities	(43,422)	30,581
Cash flows from investing activities
Purchases of property and equipment and construction in progress	(7,993)	(5,126)
Proceeds from disposal of property and equipment	22	118
Cash used in acquisitions	(288,894)	(85,499)
Net cash used in investing activities	(296,865)	(90,507)
Cash flows from financing activities
Net borrowings from floor plan	140,619	55,751
Proceeds from long-term debt	240,000	30,000
Payments on long-term debt	(13,842)	(3,334)
Payments of debt issuance costs	(4,053)	(653)
Payments of September 2020 offering costs	0	(540)
Payments of contingent consideration	(53)	0
Payments of tax withholdings for equity-based awards	(923)	(449)
Distributions to members	(6,453)	(1,520)
Net cash provided by financing activities	355,295	79,255
Net change in cash	15,008	19,329
Cash and restricted cash at beginning of period	73,949	68,153
Cash and restricted cash at end of period	88,957	87,482
Supplemental cash flow disclosures
Cash paid for interest	5,925	2,996
Cash paid for income taxes	6,310	7,480
Noncash items
Acquisition purchase price funded by seller notes payable	1,126	2,056
Acquisition purchase price funded by contingent consideration	15,321	5,482
Acquisition purchase price funded by issuance of Class A common stock	6,834	0
Purchase of property and equipment funded by long-term debt	529	1,280
Initial operating lease right-of-use assets for adoption of Topic 842	0	71,835
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 36,174	$ 17,131