Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Inventory [Line Items]
Total inventories, net	$ 609,616	$ 372,959
New vessels
Inventory [Line Items]
Total inventories, net	471,147	243,090
Pre-owned vessels
Inventory [Line Items]
Total inventories, net	61,627	51,607
Parts and accessories, work in process, net
Inventory [Line Items]
Total inventories, net	$ 76,842	$ 78,262