Long-Term Debt -Term Loan (Details) (USD $)	3 Months Ended		9 Months Ended			1 Months Ended		9 Months Ended					9 Months Ended			9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Jul. 02, 2013	Jul. 31, 2013 Term Loan [Member]	Apr. 30, 2013 Term Loan [Member]	Sep. 30, 2013 Term Loan [Member]	Sep. 30, 2014 Term Loan [Member]		Dec. 31, 2013 Term Loan [Member]	Apr. 29, 2013 Term Loan [Member]	Sep. 30, 2014 Revolving Loan [Member]		Dec. 31, 2013 Revolving Loan [Member]	Sep. 30, 2013 Prior Term Loan Facility [Member]	Apr. 29, 2013 Prior Term Loan Facility [Member]	Sep. 30, 2014 Accounts Payable, Inventory Financing [Member] Revolving Loan [Member]	Sep. 30, 2014 ABR [Member] Minimum [Member] Term Loan [Member]	Sep. 30, 2014 ABR [Member] Minimum [Member] Revolving Loan [Member]	Sep. 30, 2014 ABR [Member] Maximum [Member] Term Loan [Member]	Sep. 30, 2014 ABR [Member] Maximum [Member] Revolving Loan [Member]	Sep. 30, 2014 LIBOR [Member] Term Loan [Member]		Sep. 30, 2014 LIBOR [Member] Minimum [Member] Term Loan [Member]	Sep. 30, 2014 LIBOR [Member] Minimum [Member] Revolving Loan [Member]	Sep. 30, 2014 LIBOR [Member] Maximum [Member] Term Loan [Member]	Sep. 30, 2014 LIBOR [Member] Maximum [Member] Revolving Loan [Member]
Debt Instrument [Line Items]
Variable Interest Rate Margin																			1.25%	0.50%	1.50%	1.00%			2.25%	1.50%	2.50%	2.00%
Floorplan sub-facility, variation between balance in financials and balance per financial intermediary due to timing differences in reporting																		$ 6,300,000
Proceeds from Issuance of Long-term Debt			600,000,000	1,535,200,000			1,350,000,000
Debt, short-term and long-term									1,517,400,000		1,528,900,000		0		0		1,299,500,000
Proceeds from exercise in full of overallotment option					56,000,000
Net leverage ratio									3.2
Long-term Debt, Weighted Average Interest Rate									3.25%	[1]			0.00%	[1]									3.25%	[1]
Term Loan Repayments																40,000,000
Discount, percent of par						99.25%						99.75%
Discount, Unamortized						1,400,000			3,900,000		4,400,000	3,400,000
Variable Interest Rate, ABR Determination, Percentage Plus One-Month LIBOR													1.00%
Net loss on extinguishments of long-term debt	(45,800,000)	(41,300,000)	(53,800,000)	(55,500,000)				(10,300,000)					(400,000)
Proceeds from Issuance of Debt						190,000,000
Deferred Finance Costs, Net						$ 6,100,000							$ 6,400,000
Quarterly amortization payment of original principal, Percent									0.25%

[1] Interest rate at September 30, 2014