Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Sep. 30, 2024
Inventory [Line Items]
Total inventories	$ 539,793	$ 590,838
New vessels
Inventory [Line Items]
Total inventories	395,300	442,834
Pre-owned vessels
Inventory [Line Items]
Total inventories	74,535	79,234
Parts and accessories, work in process
Inventory [Line Items]
Total inventories	$ 69,958	$ 68,770