Stockholders’ Equity - Summary of Net (Loss) Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023
Numerator:
Net (loss) income attributable to OneWater Inc	$ (3,969)	$ 22,804	$ (11,139)	$ 31,704
Class A Common Stock
Denominator:
Weighted-average number of unrestricted outstanding common shares used to calculate basic net (loss) income per share (in shares)	14,579	14,340	14,559	14,318
Weighted Average Number of Shares Outstanding, Diluted, Adjustment [Abstract]
Diluted weighted-average shares of Class A common stock outstanding used to calculate diluted net (loss) earnings per share (in shares)	14,579	14,655	14,559	14,612
Net (loss) earnings per share of Class A common stock – basic (in usd per share)	$ (0.27)	$ 1.59	$ (0.77)	$ 2.21
Net (loss) earnings per share of Class A common stock – diluted (in usd per share)	$ (0.27)	$ 1.56	$ (0.77)	$ 2.17
Class A Common Stock | Employee Stock
Weighted Average Number of Shares Outstanding, Diluted, Adjustment [Abstract]
Restricted stock unit and employee stock purchase plan (in shares)	0	0	0	3
Class A Common Stock | Restricted Stock Units
Weighted Average Number of Shares Outstanding, Diluted, Adjustment [Abstract]
Restricted stock unit and employee stock purchase plan (in shares)	0	315	0	291