Fair Value Measurements - Additional Information (Details) - USD ($)	3 Months Ended	9 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Sep. 30, 2025
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, assets, level 1 to level 2 transfers	$ 0		$ 0		$ 0
Fair value, assets, level 2 to level 1 transfers	0		0		0
Fair value, assets, level 2 to level 3 transfers	0		0		0
Fair value, assets, level 3 to level 2 transfers	0		0		0
Fair value, assets, level 1 to level 3 transfers	0		0		0
Fair value, assets, level 3 to level 1 transfers	0		0		0
Fair value, liabilities, level 1 to level 2 transfers	0		0		0
Fair value, liabilities, level 2 to level 1 transfers	0		0		0
Fair value, liabilities, level 2 to level 3 transfers	0		0		0
Fair value, liabilities, level 3 to level 2 transfers	0		0		0
Fair value, liabilities, level 1 to level 3 transfers	0		0		0
Fair value, liabilities, level 3 to level 1 transfers	0		0		0
Reclassified out of accumulated other comprehensive income	0	$ 0	0	$ 0
Assets held for sale	$ 0		$ 0		$ 7,600,000

Fair value assets level 1 to level 2 transfer amount.

No definition available.

Name:	hzo_FairValueAssetsLevel1ToLevel2TransferAmount
Namespace Prefix:	hzo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of transfers of assets measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 3.

+ References

No definition available.

+ Details

Name:	hzo_FairValueAssetsLevel1ToLevel3TransfersAmount
Namespace Prefix:	hzo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value assets level 2 to level1 transfer amount.

+ References

No definition available.

+ Details

Name:	hzo_FairValueAssetsLevel2ToLevel1TransferAmount
Namespace Prefix:	hzo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of transfers of assets measured on a recurring basis out of Level 2 of the fair value hierarchy into Level 3.

+ References

No definition available.

+ Details

Name:	hzo_FairValueAssetsLevel2ToLevel3TransfersAmount
Namespace Prefix:	hzo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of transfers of assets measured on a recurring basis out of Level 3 of the fair value hierarchy into Level 1.

+ References

No definition available.

+ Details

Name:	hzo_FairValueAssetsLevel3ToLevel1TransfersAmount
Namespace Prefix:	hzo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of transfers of assets measured on a recurring basis out of Level 3 of the fair value hierarchy into Level 2.

+ References

No definition available.

+ Details

Name:	hzo_FairValueAssetsLevel3ToLevel2TransfersAmount
Namespace Prefix:	hzo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value liabilities level1 to level2 transfer amount.

+ References

No definition available.

+ Details

Name:	hzo_FairValueLiabilitiesLevel1ToLevel2TransferAmount
Namespace Prefix:	hzo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of transfers of liabilities measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 3.

+ References

No definition available.

+ Details

Name:	hzo_FairValueLiabilitiesLevel1ToLevel3TransfersAmount
Namespace Prefix:	hzo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value liabilities level 2 to level1 transfer amount.

+ References

No definition available.

+ Details

Name:	hzo_FairValueLiabilitiesLevel2ToLevel1TransferAmount
Namespace Prefix:	hzo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of transfers of liabilities measured on a recurring basis out of Level 2 of the fair value hierarchy into Level 3.

+ References

No definition available.

+ Details

Name:	hzo_FairValueLiabilitiesLevel2ToLevel3TransfersAmount
Namespace Prefix:	hzo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of transfers of liabilities measured on a recurring basis out of Level 3 of the fair value hierarchy into Level 1.

+ References

No definition available.

+ Details

Name:	hzo_FairValueLiabilitiesLevel3ToLevel1TransfersAmount
Namespace Prefix:	hzo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of transfers of liabilities measured on a recurring basis out of Level 3 of the fair value hierarchy into Level 2.

+ References

No definition available.

+ Details

Name:	hzo_FairValueLiabilitiesLevel3ToLevel2TransfersAmount
Namespace Prefix:	hzo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of assets held-for-sale that are not part of a disposal group, expected to be sold within a year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 852
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481372/852-10-55-10

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 15
-Paragraph 4
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482309/360-10-15-4

+ Details

Name:	us-gaap_AssetsHeldForSaleNotPartOfDisposalGroupCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name Accounting Standards Codification
-Section 55
-Paragraph 10
-SubTopic 10
-Topic 825
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482881/825-10-55-10

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482907/825-10-50-11

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482907/825-10-50-11

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482907/825-10-50-10

Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482907/825-10-50-13

Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482881/825-10-55-12

+ Details

Name:	us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, after reclassification, of tax expense (benefit) for gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness, attributable to parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 12
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482790/220-10-45-12

+ Details

Name:	us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTaxParent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration