Stockholders' Equity - Narrative (Details) $ / shares in Units, $ in Thousands					12 Months Ended			18 Months Ended
	Oct. 01, 2023 intallment shares	Jul. 19, 2021 USD ($)	Jun. 17, 2021 $ / shares	Feb. 23, 2021 shares	Sep. 30, 2023 USD ($) intallment $ / shares shares	Sep. 30, 2022 USD ($) shares	Sep. 30, 2021 USD ($)	Sep. 30, 2023 USD ($) $ / shares shares	Mar. 30, 2022 USD ($)	Dec. 31, 2021
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based payment arrangement, expense | $					$ 8,200	$ 9,800	$ 5,700
Authorized amount | $									$ 50,000
Repurchase and retirement of shares amount | $					1,579	354
Stock repurchase program, remaining authorized repurchase amount | $					48,100			$ 48,100
Equity-based compensation | $					8,962	$ 10,013	5,741
Common stock, dividends | $					$ 500
Share-Based Payment Arrangement, Tranche One
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Performance targets achieved, percentage					100.00%			100.00%
Quality Boats
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Percentage of economic interest retained by sellers					80.00%			80.00%		20.00%
Percentage of remaining economic interest					20.00%			20.00%
OneWater LLC
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Ownership interest of parent					91.00%			91.00%
Noncontrolling interest, ownership percentage by noncontrolling owners					9.00%			9.00%
Employee Stock Purchase Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Shares issued as part of employee stock purchase plan (in shares)					86,050	0
Equity-based compensation | $					$ 700	$ 200
Stock to be purchased under ESPP | $					$ 400	$ 500
Class A Common Stock
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Capital shares reserved for future issuance (in shares)						1,585,007
Repurchase and retirement of Class A common stock (in shares)					63,353			73,487
Repurchase and retirement of shares amount | $					$ 1,600			$ 1,900
Percentage of outstanding shares, ESPP issuance				1.00%
Common stock, dividends (in usd per share) | $ / shares			$ 1.80
Common stock, dividends | $		$ 27,100
Ratio of shares converted					1
Class A Common Stock | Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Shares issued as part of employee stock purchase plan (in shares)				449,257
Class B Common Stock
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Ratio of shares converted					1
Time-Based Restricted Stock Units
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Awarded (in shares)					137,057
Time-Based Restricted Stock Units | Subsequent Event
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Awarded (in shares)	114,507
Vested (in shares)	22,550
Number of equal annual installments for vesting | intallment	3
Performance Shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Awarded (in shares)					88,018
Percentage of target award granted					100.00%
Number of shares of common stock consisted in each unit (in shares)					1
Share-based payment arrangement, expense | $					$ 3,500	$ 5,400	$ 2,600
Performance Shares | Share-Based Payment Arrangement, Tranche One
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Awarded (in shares)					13,288
Performance Shares | Share-Based Payment Arrangement, Tranche Two
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Awarded (in shares)					74,730
Number of equal annual installments for vesting | intallment					3
Performance targets achieved of installment awards, percentage					40.00%			40.00%
Restricted stock units
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Awarded (in shares)					225,075	225,924
Vested (in shares)					257,082	211,225
Nonvested award | $					$ 3,300			$ 3,300
Cost not yet recognized, period for recognition					1 year 1 month 6 days
Employee Stock Purchase Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Shares issued (in shares) | $ / shares					$ 24.31			$ 24.31
Restricted Stock
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Payments of dividends | $					$ 300	$ 200
Restricted Stock | Class A Common Stock
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common stock, dividends | $		$ 1,000