Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended				9 Months Ended		12 Months Ended
	Sep. 30, 2025	Mar. 31, 2025	Sep. 30, 2024	Mar. 31, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Operating activities
Net income (loss)	$ (29,351)	$ (24,682)	$ 8,056	$ (50,806)	$ 3,490	$ (19,336)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	25,654		20,583		71,617	59,905
Stock-based compensation					23,464	16,167
Gain on lease termination					(154)	(2,585)
Long-lived asset impairment	617		1,944		1,237	12,355
(Gain) loss on sale or disposal of assets	534		(5)		(104)	9,525
Provision for losses on accounts receivable					1,796	412
Noncash lease expense					44,566	42,475
Accretion of original debt issuance discount					1,934	1,790
Noncash interest					3,208	2,339
Deferred income taxes					213,645	(560)
Tax Receivable Agreement liability adjustment	(149,172)		0		(149,172)	0
Change in assets and liabilities, net of acquisitions:
Receivables and contracts in transit					(57,016)	(38,543)
Inventories					(136,973)	270,061
Prepaid expenses and other assets					(1,013)	(8,683)
Accounts payable and other accrued expenses					119,078	113,413
Payment pursuant to Tax Receivable Agreement					0	(12,943)
Deferred revenues					4,371	9,394
Operating lease liabilities					(47,409)	(48,428)
Other, net					(1,329)	1,783
Net cash provided by operating activities					95,236	408,541
Investing activities
Purchases of property and equipment					(84,130)	(68,194)
Proceeds from sale or disposal of property and equipment					3,650	3,820
Purchases of real property					(122,842)	(1,243)
Proceeds from the sale or disposal of real property					53,769	48,434
Purchases of businesses, net of cash acquired					(81,203)	(62,323)
Proceeds from divestiture of business					11,027	19,957
Purchases of other investments					(6,668)	0
Proceeds from other investments					326	0
Purchases of intangible assets					0	(142)
Proceeds from sale of intangible assets					0	2,595
Net cash used in investing activities					(226,071)	(57,096)
Financing activities
Proceeds from long-term debt					0	55,624
Payments on long-term debt					(38,223)	(66,763)
Net proceeds (payments) on notes payable - floor plan, net					226,342	(317,519)
Borrowings on revolving line of credit					0	43,000
Payments on revolving line of credit					0	(32,000)
Payments on finance leases					(5,540)	(5,684)
Payments on sale-leaseback arrangement					(151)	(147)
Payment of debt issuance costs					0	(876)
Payments of stock offering costs					(572)	0
Dividends on Class A common stock					(23,504)	(16,940)
Proceeds from exercise of stock options					0	549
RSU shares withheld for tax					(2,940)	(3,110)
Distributions to holders of LLC common units					(2,486)	(18,846)
Net cash provided by (used in) financing activities					152,926	(362,712)
Increase (decrease) in cash and cash equivalents					22,091	(11,267)
Cash and cash equivalents at beginning of the period		$ 208,422		$ 39,647	208,422	39,647	$ 39,647
Cash and cash equivalents at end of the period	$ 230,513		$ 28,380		$ 230,513	$ 28,380	$ 208,422