Acquisitions (Details) $ in Thousands	3 Months Ended
	Dec. 31, 2021 USD ($) Location	Dec. 31, 2020 USD ($)	Dec. 01, 2021 Location	Oct. 02, 2021 Location	Sep. 30, 2021 USD ($)
Acquisition [Abstract]
Cash paid for acquisition	$ 278,800
Note payable to seller	1,100
Payment of contingent consideration	10,000
Accrued purchase consideration	5,400
Issuance of shares of Class A common stock	6,800
Minimum payout due of contingent consideration	0
Maximum payout due of contingent consideration	18,800
Summary of Assets Acquired and Liabilities Assumed [Abstract]
Goodwill	419,675				$ 168,491
Revenue	336,272	$ 214,083
Income before income tax expense	28,375	14,286
Costs related to acquisition	3,045	200
Unaudited Pro Forma Results of Operations [Abstract]
Pro forma revenue	374,940	318,198
Pro forma net income	$ 23,949	$ 17,803
Notes Payable [Member]
Acquisition [Abstract]
Interest rate	4.00%
Naples Boat Mart [Member]
Acquisition [Abstract]
Number of stores | Location				1
Norfolk Marine [Member]
Acquisition [Abstract]
Number of stores | Location			1
T-H Marine [Member]
Summary of Assets Acquired and Liabilities Assumed [Abstract]
Accounts receivable	$ 8,955
Inventories	19,856
Prepaid expenses	1,547
Property and equipment	3,896
Operating lease right-of-use assets	5,960
Identifiable intangible assets	0
Goodwill	157,367
Accounts payable	(3,876)
Accrued expenses	(1,870)
Customer deposits	(394)
Operating lease liabilities	(5,960)
Aggregate acquisition date fair value	185,481
Consideration transferred	185,481
Fair value of non-controlling interests	$ 0
Quality Boats [Member]
Acquisition [Abstract]
Number of stores | Location	3
Percentage of economic interest retained by sellers	20.00%
Percentage of remaining economic interest	20.00%
Summary of Assets Acquired and Liabilities Assumed [Abstract]
Accounts receivable	$ 0
Inventories	5,937
Prepaid expenses	187
Property and equipment	803
Operating lease right-of-use assets	428
Identifiable intangible assets	31,700
Goodwill	78,682
Accounts payable	(2,108)
Accrued expenses	0
Customer deposits	(3,997)
Operating lease liabilities	(428)
Aggregate acquisition date fair value	111,204
Consideration transferred	91,893
Fair value of non-controlling interests	19,311
Other Acquisitions [Member]
Summary of Assets Acquired and Liabilities Assumed [Abstract]
Accounts receivable	399
Inventories	6,879
Prepaid expenses	56
Property and equipment	916
Operating lease right-of-use assets	0
Identifiable intangible assets	4,250
Goodwill	15,135
Accounts payable	(219)
Accrued expenses	(483)
Customer deposits	(2,227)
Operating lease liabilities	0
Aggregate acquisition date fair value	24,706
Consideration transferred	24,706
Fair value of non-controlling interests	0
Total Acquisitions [Member]
Summary of Assets Acquired and Liabilities Assumed [Abstract]
Accounts receivable	9,354
Inventories	32,672
Prepaid expenses	1,790
Property and equipment	5,615
Operating lease right-of-use assets	6,388
Identifiable intangible assets	35,950
Goodwill	251,184
Accounts payable	(6,203)
Accrued expenses	(2,353)
Customer deposits	(6,618)
Operating lease liabilities	(6,388)
Aggregate acquisition date fair value	321,391
Consideration transferred	302,080
Fair value of non-controlling interests	19,311
Revenue	14,200
Income before income tax expense	$ 1,100