Credit Facilities (Details Textual) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2015 USD ($) loan	Sep. 30, 2015 USD ($) loan	Dec. 31, 2014 USD ($)
Line of Credit Facility [Line Items]
Assets Held-for-sale, Long Lived	$ (20,001)	$ (20,001)	$ (22,500)
Floorplan Offset	(28,073)	$ (28,073)	(39,616)
FMCC Facility [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.50%
Maximum borrowing capacity under line of credit facility	300,000	$ 300,000
Line of Credit Facility, Amount Outstanding	126,800	126,800
Available amount under borrowing capacity	$ 173,200	$ 173,200
Cancellation of agreement	30 days
Debt interest rate	4.75%	4.75%
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity under line of credit facility	$ 1,700,000	$ 1,700,000
Line Of Credit Facility Maximum Borrowing Capacity Can Be Extended Amount	$ 1,950,000	$ 1,950,000
Number of financial institutions | loan	24	24
Number of Manufacturer-affiliated finance companies | loan	6	6
Expiry date of Revolving Credit Facility	Jun. 20, 2018
Number of tranches	2	2
Acquisition Line Minimum Commitment	$ 100,000	$ 100,000
Line of credit facility, Unamortized Cost	4,100	4,100
Restricted payment	162,100	162,100
Maximum Limit Of Restricted Payment Basket	$ 125,000	$ 125,000
Rental Vehicle Credit Facility [Member]
Line of Credit Facility [Line Items]
Debt interest rate	4.75%	4.75%
Maximum [Member] | Brazil Credit Facilities [Member]
Line of Credit Facility [Line Items]
Debt interest rate	23.73%	23.73%
Debt Instrument Maturity Date Period	12 months
Maximum [Member] | UK Credit Facilities [Member]
Line of Credit Facility [Line Items]
Debt interest rate	3.95%	3.95%
Minimum [Member] | Brazil Credit Facilities [Member]
Line of Credit Facility [Line Items]
Debt interest rate	16.77%	16.77%
Debt Instrument Maturity Date Period	1 month
Minimum [Member] | UK Credit Facilities [Member]
Line of Credit Facility [Line Items]
Debt interest rate	1.15%	1.15%
Acquisition Line [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.50%
Maximum borrowing capacity under line of credit facility	$ 320,000	$ 320,000
Line Of Credit Facility, Minimum Borrowing Capacity	100,000	100,000
Line of Credit Facility, Amount Outstanding	138,201	138,201	$ 69,713
Available amount under borrowing capacity	122,000	122,000
Letters of credit outstanding	45,700	45,700
Acquisition Line [Member] | Revolving Credit Facility [Member] | United States of America, Dollars
Line of Credit Facility [Line Items]
Line of Credit Facility, Amount Outstanding	138,200	138,200
Acquisition Line [Member] | Revolving Credit Facility [Member] | Euros or Pound Sterling [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity under line of credit facility	$ 125,000	$ 125,000
Acquisition Line [Member] | Maximum [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Commitment fees, Percentage	0.45%
Acquisition Line [Member] | Maximum [Member] | Revolving Credit Facility [Member] | United States of America, Dollars
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.00%
Acquisition Line [Member] | Maximum [Member] | Revolving Credit Facility [Member] | Euros or Pound Sterling [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate		2.50%
Acquisition Line [Member] | Minimum [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Commitment fees, Percentage	0.25%
Acquisition Line [Member] | Minimum [Member] | Revolving Credit Facility [Member] | United States of America, Dollars
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate		0.00%
Acquisition Line [Member] | Minimum [Member] | Revolving Credit Facility [Member] | Euros or Pound Sterling [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.50%
Floorplan Line [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity under line of credit facility	$ 1,600,000	$ 1,600,000
Commitment fees, Percentage	0.20%
Line of Credit Facility, Amount Outstanding	$ 1,148,300	1,148,300
Available amount under borrowing capacity	231,700	231,700
Floorplan Offset	$ (28,100)	$ (28,100)
Weighted average interest rate	1.40%	1.40%	1.40%
Maximum period for outstanding borrowing	1 year
Floorplan Line [Member] | New Vehicles [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.25%
Floorplan Line [Member] | Used Vehicles [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.50%