Long-Term Debt -Revolving Loan (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Revolving Loan [Member]
Debt Instrument [Line Items]
Debt, short-term and long-term	$ 0	$ 0
Floorplan sub-facility, reserve	248,400,000
Revolving Commitment	900,000,000
Revolving loan financing agreement, percentage reserve for open orders	15.00%
Borrowing Base	1,107,400,000
Availability under Revolving Loan	649,400,000
Letter of Credit [Member]
Debt Instrument [Line Items]
Undrawn letters of credit	2,200,000
Accounts Payable, Inventory Financing [Member]
Debt Instrument [Line Items]
Floorplan sub-facility, reserve	9,700,000
Amount owed under Revolving loan financing agreement	238,700,000
Floorplan sub-facility, variation between balance in financials and balance per financial intermediary due to timing differences in reporting	$ 11,400,000
Lower Utilization [Member] | Revolving Loan [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Fee on Unused Portion, Basis Points	50
Higher Utilization [Member] | Revolving Loan [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Fee on Unused Portion, Basis Points	37.5