Inventories (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Sep. 30, 2021
Component of Inventory [Abstract]
Inventories, net	$ 269,430	$ 143,880
New Vessels [Member]
Component of Inventory [Abstract]
Inventories, net	182,184	105,625
Pre-owned Vessels [Member]
Component of Inventory [Abstract]
Inventories, net	37,443	22,906
Work in Process, Parts and Accessories, Net [Member]
Component of Inventory [Abstract]
Inventories, net	$ 49,803	$ 15,349