CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Revenues
Total revenues		$ 1,228,206	$ 1,022,970
Cost of sales (exclusive of depreciation and amortization shown separately below)
Total cost of sales		870,751	787,446
Selling, general and administrative expenses		199,049	143,575
Depreciation and amortization		5,411	3,249	$ 2,682
Transaction costs		869	3,648	1,300
Loss on contingent consideration		3,249	6,762
Income from operations		148,877	78,290
Other expense (income)
Interest expense - floor plan		2,566	8,861
Interest expense - other		4,344	8,828
Change in fair value of warrant liability		0	(771)	(1,336)
Loss on extinguishment of debt		0	6,559	0
Other (income) expense, net		(248)	(24)
Total other expense, net		6,662	23,453
Income before income tax expense		142,215	54,837
Income tax expense		25,802	6,329
Net income		116,413	48,508	37,263
Less: Net income attributable to non-controlling interest		37,354	30,733
Net (loss) income attributable to One Water Marine Holdings, LLC		79,059	17,425
New Boat [Member]
Revenues
Total revenues		872,680	717,093
Cost of sales (exclusive of depreciation and amortization shown separately below)
Total cost of sales		661,764	585,720
Pre-Owned Boat [Member]
Revenues
Total revenues		216,416	205,650
Cost of sales (exclusive of depreciation and amortization shown separately below)
Total cost of sales		162,278	168,261
Finance & Insurance [Member]
Revenues
Total revenues		42,668	36,792
Service, Parts & Other [Member]
Revenues
Total revenues		96,442	63,435
Cost of sales (exclusive of depreciation and amortization shown separately below)
Total cost of sales		$ 46,709	$ 33,465
Class A Common Stock [Member]
Other expense (income)
Earnings per share, Basic (in dollars per share)	[1]	$ 7.13	$ 2.79
Earnings per share, Diluted (in dollars per share)	[1]	$ 6.96	$ 2.77
Basic weighted-average shares outstanding (in shares)	[1]	11,087	6,243
Diluted weighted-average shares outstanding (in shares)	[1]	11,359	6,287
OneWater LLC [Member]
Revenues
Total revenues				767,624
Cost of sales (exclusive of depreciation and amortization shown separately below)
Total cost of sales				595,498
Selling, general and administrative expenses				116,503
Depreciation and amortization				2,682
Transaction costs				1,323
Loss on contingent consideration				(1,674)
Income from operations				53,292
Other expense (income)
Interest expense - floor plan				9,395
Interest expense - other				6,568
Change in fair value of warrant liability				(1,336)
Loss on extinguishment of debt				0
Other (income) expense, net				1,402
Total other expense, net				16,029
Income before income tax expense				37,263
Income tax expense				0
Net income				37,263
Less: Net income attributable to non-controlling interest			$ 350	1,606
Net (loss) income attributable to One Water Marine Holdings, LLC				35,657
OneWater LLC [Member] | New Boat [Member]
Revenues
Total revenues				526,774
Cost of sales (exclusive of depreciation and amortization shown separately below)
Total cost of sales				434,242
OneWater LLC [Member] | Pre-Owned Boat [Member]
Revenues
Total revenues				153,010
Cost of sales (exclusive of depreciation and amortization shown separately below)
Total cost of sales				127,018
OneWater LLC [Member] | Finance & Insurance [Member]
Revenues
Total revenues				26,151
OneWater LLC [Member] | Service, Parts & Other [Member]
Revenues
Total revenues				61,689
Cost of sales (exclusive of depreciation and amortization shown separately below)
Total cost of sales				$ 34,238

[1] For the fiscal year ended September 30, 2020, represents earnings per share of Class A common stock and weighted-average shares of Class A common stock outstanding for the period from February 11, 2020 through September 30, 2020, the period following OneWater Marine Inc.’s initial public offering. See Note 1.