Stockholders’ Equity - Narrative (Details) $ / shares in Units, $ in Thousands					3 Months Ended		6 Months Ended	9 Months Ended		33 Months Ended
	Oct. 02, 2024 intallment shares	Oct. 01, 2024 shares	Oct. 02, 2023 intallment	Feb. 23, 2021 shares	Jun. 30, 2026 USD ($) $ / shares shares	Jun. 30, 2025 USD ($) $ / shares shares	Mar. 31, 2026 shares	Jun. 30, 2026 USD ($) $ / shares shares	Jun. 30, 2025 USD ($) $ / shares shares	Dec. 31, 2024 USD ($) shares	Sep. 30, 2025 USD ($)	Mar. 30, 2022 USD ($)
Share-Based Payment Arrangement [Abstract]
Percentage of expected performance targets to be achieved target award					135.00%			135.00%
Authorized amount | $												$ 50,000
Stock repurchase program, remaining authorized repurchase amount | $					$ 48,100			$ 48,100
Equity-based awards | $					4,006	$ 2,459		8,947	$ 6,717
Net income (loss) attributable to OneWater Inc | $					11,673	10,715		$ (8,939)	(1,624)
Employee Stock
Share-Based Payment Arrangement [Abstract]
Equity-based awards | $					$ 100	100
OneWater LLC
Share-Based Payment Arrangement [Abstract]
Ownership interest in subsidiaries					100.00%			100.00%
Performance Shares
Share-Based Payment Arrangement [Abstract]
Awarded (in shares)								384,472
Percentage of target award granted								100.00%
Number of shares of common stock consisted in each unit (in shares)								1
Number of equal annual installments for vesting | intallment			3
Share-based payment arrangement, expense | $					$ 2,400	1,200		$ 4,200	2,700
Time-Based Restricted Stock Units
Share-Based Payment Arrangement [Abstract]
Awarded (in shares)	371,814	61,343						433,157
Number of equal annual installments for vesting | intallment	3
Restricted Stock Units
Share-Based Payment Arrangement [Abstract]
Awarded (in shares)								817,629,000
Share-based payment arrangement, expense | $					3,900	$ 2,300		$ 8,700	$ 6,300
Nonvested award | $					9,600			$ 9,600
Cost not yet recognized, period for recognition								1 year 3 months 18 days
Employee Stock
Share-Based Payment Arrangement [Abstract]
Shares issued as part of employee stock purchase plan (in shares)								47,463	36,167
Equity-based awards | $								$ 300	$ 400
Stock to be purchased under ESPP | $					$ 400			$ 400			$ 200
Shares Issued, Price Per Share | $ / shares					$ 9.20	$ 14.77		$ 9.20	$ 14.77
Class A Common Stock
Share-Based Payment Arrangement [Abstract]
Capital shares reserved for future issuance (in shares)					1,661,966			1,661,966
Repurchased shares (in shares)					0
Repurchased and retired shares (in shares)										73,487
Repurchase and retirement of shares amount | $										$ 1,900
Percentage of outstanding shares, ESPP issuance				1.00%
Exchange of B shares for A shares (in shares)							1,429,940
Weighted-average number of unrestricted outstanding common shares used to calculate basic net (loss) income per share (in shares)					16,618,000	16,313,000		16,588,000	15,700,000
Diluted weighted-average shares of Class A common stock outstanding used to calculate diluted earnings per share (in shares)					16,954,000	16,444,000		16,588,000	15,700,000
Net loss per share of Class A common stock – basic (in usd per share) | $ / shares					$ 0.70	$ 0.66		$ (0.54)	$ (0.10)
Net (loss) earnings per share of Class A common stock – diluted (in usd per share) | $ / shares					$ 0.69	$ 0.65		$ (0.54)	$ (0.10)
Class A Common Stock | Employee Stock
Share-Based Payment Arrangement [Abstract]
Restricted stock unit and employee stock purchase plan (in shares)					3,000	11,000		0	0
Class A Common Stock | Maximum
Share-Based Payment Arrangement [Abstract]
Shares issued as part of employee stock purchase plan (in shares)				612,434
Class A Common Stock | Restricted Stock Units
Share-Based Payment Arrangement [Abstract]
Restricted stock unit and employee stock purchase plan (in shares)					333,000	120,000		0	0
Class B Common Stock
Share-Based Payment Arrangement [Abstract]
Exchange of B shares for A shares (in shares)							1,429,940