XML 54 R40.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Significant Accounting Policies - Summary of Percentages of Revenue Generated by Products and Services (Detail) - Product Concentration Risk [Member] - Sales [Member] | 12 Months Ended
--- | ---
Sep. 30, 2017 | Sep. 30, 2016 | Sep. 30, 2015
Product Information [Line Items] |  |  |
Sales Revenue Goods And Services Net Percentage | 100.00% | 100.00% | 100.00%
New Boat Sales [Member] |  |  |
Product Information [Line Items] |  |  |
Sales Revenue Goods And Services Net Percentage | 70.90% | 68.50% | 64.30%
Used Boat Sales [Member] |  |  |
Product Information [Line Items] |  |  |
Sales Revenue Goods And Services Net Percentage | 14.90% | 17.50% | 19.90%
Maintenance, Repair, Storage and Charter Services [Member] |  |  |
Product Information [Line Items] |  |  |
Sales Revenue Goods And Services Net Percentage | 6.30% | 6.00% | 6.90%
Finance and Insurance Products [Member] |  |  |
Product Information [Line Items] |  |  |
Sales Revenue Goods And Services Net Percentage | 2.40% | 2.50% | 2.50%
Parts and Accessories [Member] |  |  |
Product Information [Line Items] |  |  |
Sales Revenue Goods And Services Net Percentage | 3.60% | 3.50% | 4.10%
Brokerage Sales [Member] |  |  |
Product Information [Line Items] |  |  |
Sales Revenue Goods And Services Net Percentage | 1.90% | 2.00% | 2.30%

X
- Definition For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=84177426&loc=d3e6351-108592 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13531-108611 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=84177426&loc=d3e6404-108592 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13537-108611 + Details
Name: | us-gaap_ConcentrationRiskPercentage1
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- 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 No definition available. + Details
Name: | us-gaap_ProductInformationLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_ConcentrationRiskByTypeAxis=us-gaap_ProductConcentrationRiskMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_SalesRevenueNetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ProductOrServiceAxis=hzo_NewBoatSalesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ProductOrServiceAxis=hzo_UsedBoatSalesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ProductOrServiceAxis=hzo_MaintenanceRepairStorageAndCharterServicesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ProductOrServiceAxis=hzo_FinanceAndInsuranceProductsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ProductOrServiceAxis=hzo_PartsAndAccessoriesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ProductOrServiceAxis=hzo_BrokerageSalesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |