Company Background - Additional Information (Detail)	3 Months Ended		12 Months Ended
	Dec. 31, 2023 Location	Dec. 31, 2022	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2023 RetailDealership	Dec. 31, 2023 Marina
Concentration Risk [Line Items]
Number of retail locations	130					81	66
Product Concentration Risk [Member] | Sales [Member]
Concentration Risk [Line Items]
Revenue percentage from sale of boats	100.00%	100.00%
Product Concentration Risk [Member] | Brunswick [Member] | Sales [Member]
Concentration Risk [Line Items]
Revenue percentage from sale of boats			24.00%
Product Concentration Risk [Member] | Brunswick Sea Ray Boat [Member] | Brunswick [Member] | Sales [Member]
Concentration Risk [Line Items]
Revenue percentage from sale of boats			11.00%
Product Concentration Risk [Member] | Brunswick Boston Whaler Boats [Member] | Brunswick [Member] | Sales [Member]
Concentration Risk [Line Items]
Revenue percentage from sale of boats			11.00%
Product Concentration Risk [Member] | Azimut Benetti Groups and Yachts | Sales [Member]
Concentration Risk [Line Items]
Revenue percentage from sale of boats			11.00%
Geographic Concentration Risk [Member] | Sales [Member] | Florida [Member]
Concentration Risk [Line Items]
Revenue percentage from sale of boats			53.00%	51.00%	50.00%