Description of Company and Basis of Presentation (Details)	3 Months Ended
	Dec. 31, 2020 Store State Brand	Dec. 31, 2019
Description of the Business [Abstract]
Number of stores operating | Store	69
Number of states in which stores operating | State	10
Number of top brands | Brand	10
OneWater LLC [Member]
Principles of Consolidation [Abstract]
Ownership interest in subsidiaries	72.60%
Sales Revenue [Member]
Description of the Business [Abstract]
Concentration risk percentage	41.20%	41.80%
Sales Revenue [Member] | Malibu Boats, Inc [Member]
Description of the Business [Abstract]
Concentration risk percentage	13.70%	15.30%