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Percentage of aggerate principal balance required for quarterly installment payments.

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Value of preferred stock issued during the period upon the conversion net of issuance costs.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Investors (FY) (Details) - USD ($) $ in Thousands		9 Months Ended		12 Months Ended
Investors (FY) (Details) - USD ($) $ in Thousands	Oct. 28, 2016	Jun. 30, 2020	Jun. 30, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017	May 01, 2019	Feb. 01, 2018	Sep. 30, 2016
Investors [Abstract]
Payment of equity distributions		$ 11,618	$ 9,887
Warrants [Member]
Investors [Abstract]
Common unit warrants issued (in shares)	25,000
Common unit warrants in exchange price	$ 1,000
One Water Assets & Operations [Member]
Investors [Abstract]
Preferred units outstanding (in shares)									68,000
OneWater LLC [Member]
Investors [Abstract]
Payment of equity distributions	41,300			$ 11,087	$ 3,256	$ 47,202
Related party advance amount	1,500
Equity syndication costs	2,100					$ 2,100
Debt issuance costs	$ 900
OneWater LLC [Member] \| Warrants [Member]
Investors [Abstract]
Common unit warrants issued (in shares)	25,000
Common unit warrants in exchange price	$ 1,000
OneWater LLC [Member] \| One Water Assets & Operations [Member]
Investors [Abstract]
Preferred units outstanding (in shares)	68,000								68,000
Cash consideration received on exchange of shares	$ 67,000
OneWater LLC [Member] \| Line of Credit [Member]
Investors [Abstract]
Repayment of debt	2,200
OneWater LLC [Member] \| Notes Payable [Member]
Investors [Abstract]
Repayment of debt	20,400
OneWater LLC [Member] \| Related Party Notes Payable [Member]
Investors [Abstract]
Repayment of debt	1,000
OneWater LLC [Member] \| Multi-Draw Term Loan with GS and BIP [Member]
Investors [Abstract]
Face amount of debt	$ 20,000						$ 60,000	$ 50,000
Interest rate	10.00%			10.00%
Frequency of periodic payment				Quarterly
Percentage of Quarterly Principal Payments of Aggregate Principal Balance	5.00%
Maturity date				Oct. 28, 2021