Summary of Significant Accounting Policies - Restricted Cash (Details)	Sep. 30, 2017
Floor Plan Facility \| Line of Credit
Debt Instrument [Line Items]
Deposit required under floor plan facility, percentage of principal balance	5.00%

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.

No definition available.

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