Inventories (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Sep. 30, 2021
Component of Inventory [Abstract]
Inventories	$ 293,170	$ 143,880
New Vessels [Member]
Component of Inventory [Abstract]
Inventories	213,420	105,625
Pre-owned Vessels [Member]
Component of Inventory [Abstract]
Inventories	32,532	22,906
Work in Process, Parts and Accessories [Member]
Component of Inventory [Abstract]
Inventories	$ 47,218	$ 15,349

Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
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Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 10
-Section 55
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant