Long-Term Debt -Term Loan (Details) (USD $)	3 Months Ended			1 Months Ended		12 Months Ended					3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Jul. 02, 2013	Jul. 31, 2013 Term Loan [Member]	Apr. 30, 2013 Term Loan [Member]	Dec. 31, 2013 Term Loan [Member]	Mar. 31, 2014 Term Loan [Member]	Apr. 29, 2013 Term Loan [Member]	Mar. 31, 2014 Revolving Loan [Member]	Dec. 31, 2013 Revolving Loan [Member]	Mar. 31, 2014 Prior Term Loan Facility [Member]	Mar. 31, 2013 Prior Term Loan Facility [Member]	Mar. 31, 2014 Accounts Payable, Inventory Financing [Member]	Mar. 31, 2014 ABR [Member] Minimum [Member] Term Loan [Member]	Mar. 31, 2014 ABR [Member] Maximum [Member] Term Loan [Member]
Debt Instrument [Line Items]
Variable Interest Rate Margin														1.25%	1.50%
Floorplan sub-facility, variation between balance in financials and balance per financial intermediary due to timing differences in reporting													$ 11,400,000
Proceeds from Issuance of Long-term Debt					1,350,000,000
Debt, short-term and long-term						1,528,900,000	1,525,100,000		0	0		1,299,500,000
Proceeds from exercise in full of overallotment option			56,000,000
Net leverage ratio							3.5
Term Loan Repayments											40,000,000
Discount, percent of par				99.25%				99.75%
Discount, Unamortized				1,400,000		4,400,000	4,200,000	3,400,000
Variable Interest Rate, ABR Determination, Percentage Plus One-Month LIBOR							1.00%
Net loss on extinguishments of long-term debt	(5,400,000)	(3,900,000)				(10,300,000)
Proceeds from Issuance of Debt				190,000,000
Deferred Finance Costs, Net				$ 6,100,000