v3.26.1
Revenue Recognition - Summary of Revenue Disaggregated Into Categories Depict the Nature, Amount, Timing, and Uncertainty of Revenue and Cash Flows Affected by Economic Factor (Details) - Sales [Member] - Product Concentration Risk [Member]
 3 Months Ended 9 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Product Information [Line Items]        
Sales Revenue Goods And Services Net Percentage 100.00% 100.00% 100.00% 100.00%
Retail Operations [Member]        
Product Information [Line Items]        
Sales Revenue Goods And Services Net Percentage 100.00% 100.00% 100.00% 100.00%
Product Manufacturing [Member]        
Product Information [Line Items]        
Sales Revenue Goods And Services Net Percentage 100.00% 100.00% 100.00% 100.00%
New Boat Sales [Member]        
Product Information [Line Items]        
Sales Revenue Goods And Services Net Percentage 59.30% 63.60% 61.70% 62.70%
New Boat Sales [Member] | Retail Operations [Member]        
Product Information [Line Items]        
Sales Revenue Goods And Services Net Percentage 59.20% 63.20% 61.40% 62.30%
New Boat Sales [Member] | Product Manufacturing [Member]        
Product Information [Line Items]        
Sales Revenue Goods And Services Net Percentage 95.20% 98.40% 97.60% 98.70%
Used Boat Sales [Member]        
Product Information [Line Items]        
Sales Revenue Goods And Services Net Percentage 12.20% 12.20% 10.30% 12.50%
Used Boat Sales [Member] | Retail Operations [Member]        
Product Information [Line Items]        
Sales Revenue Goods And Services Net Percentage 12.30% 12.20% 10.40% 12.60%
Maintenance and Repair Services [Member]        
Product Information [Line Items]        
Sales Revenue Goods And Services Net Percentage 5.50% 5.10% 5.20% 5.00%
Maintenance and Repair Services [Member] | Retail Operations [Member]        
Product Information [Line Items]        
Sales Revenue Goods And Services Net Percentage 5.50% 5.20% 5.20% 5.00%
Storage and Charter Rentals [Member]        
Product Information [Line Items]        
Sales Revenue Goods And Services Net Percentage 8.00% 6.40% 9.20% 7.50%
Storage and Charter Rentals [Member] | Retail Operations [Member]        
Product Information [Line Items]        
Sales Revenue Goods And Services Net Percentage 8.00% 6.70% 9.30% 7.80%
Finance and Insurance Products [Member]        
Product Information [Line Items]        
Sales Revenue Goods And Services Net Percentage 3.80% 3.60% 3.60% 3.40%
Finance and Insurance Products [Member] | Retail Operations [Member]        
Product Information [Line Items]        
Sales Revenue Goods And Services Net Percentage 3.80% 3.60% 3.60% 3.40%
Parts and Accessories [Member]        
Product Information [Line Items]        
Sales Revenue Goods And Services Net Percentage 5.70% 4.60% 5.40% 4.60%
Parts and Accessories [Member] | Retail Operations [Member]        
Product Information [Line Items]        
Sales Revenue Goods And Services Net Percentage 5.70% 4.60% 5.40% 4.60%
Parts and Accessories [Member] | Product Manufacturing [Member]        
Product Information [Line Items]        
Sales Revenue Goods And Services Net Percentage 4.80% 1.60% 2.40% 1.30%
Brokerage Sales [Member]        
Product Information [Line Items]        
Sales Revenue Goods And Services Net Percentage 5.50% 4.50% 4.60% 4.30%
Brokerage Sales [Member] | Retail Operations [Member]        
Product Information [Line Items]        
Sales Revenue Goods And Services Net Percentage 5.50% 4.50% 4.70% 4.30%