Interest Rate Swaps (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
Jun. 30, 2010	Jun. 30, 2011
Trading Activity, Gains and Losses, Net [Line Items]
Portion of floating rate floor plan debt fixed by swap agreements		$ 300,000
Interest Rate Swaps (Textuals) [Abstract]
Interest rate swap, fixed		3.67%
Estimated liabilities of swaps designated as hedging instruments, fair value		6,259
Net gain recognized in accumulated other comprehensive income	1,328
Losses reclassified from accumulated other comprehensive income into floor plan interest expense	2,207
Increase in the weighted average interest rate on floor plan borrowings due to the swaps	0.40%
Forward Starting Interest Rate Swap Agreements [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Portion of floating rate floor plan debt fixed by swap agreements		300,000
Derivative, Variable Interest Rate		2.135%
Floating Rate Floor Plan Debt [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Portion of floating rate floor plan debt fixed by swap agreements		$ 100,000
Derivative, Variable Interest Rate		1.55%

Total monetary amount specified by the derivative(s). Expressed as an absolute value.

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- Definition

Interest Rate Swaps.

+ Details

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- Definition

Fixed interest rate related to the interest rate derivative.

+ Details

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- Definition

Fair value of a derivative liability (or nonderivative instrument) that is designated and qualifies as a hedging instrument, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 205G

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 44C
-Subparagraph a
-Clause 1

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- Definition

Variable interest rate in effect as of the balance sheet date related to the interest rate derivative.

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- Definition

The amount of net gains (losses) on interest rate cash flow hedges reclassified during the period to earnings from accumulated other comprehensive income upon the hedged transaction affecting earnings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 45
-Subparagraph b(1)

+ Details

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- Definition

Reflects the calculation as of the balance-sheet date of the average interest rate weighted by the amount of short-term debt outstanding by type or by instrument at that time.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19
-Subparagraph b
-Article 5

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- 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.

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- Definition

Amount of unrealized gain (loss) related to the increase (decrease) in fair value of interest rate derivatives designated as cash flow hedging instruments, which was recorded in accumulated other comprehensive income to the extent that the cash flow hedge was determined to be effective.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 46

+ Details

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