Credit Facilities (Details Textual) $ in Thousands	3 Months Ended
	Jun. 30, 2017 USD ($) loan	Dec. 31, 2016 USD ($)
Line of Credit Facility [Line Items]
Floorplan Offset	$ (55,579)	$ (59,626)
FMCC Offset	(21,000)	$ (25,500)
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity under line of credit facility	$ 1,800,000
Expiry date of Revolving Credit Facility	Jun. 17, 2021
Number of financial institutions | loan	24
Number of Manufacturer-affiliated finance companies | loan	6
Number of tranches	2
Line Of Credit Facility Maximum Borrowing Capacity Can Be Extended Amount	$ 2,100,000
Line of credit facility, Unamortized Cost	$ 4,800
Maximum Limit Of Restricted Payment Basket	the sum of $208.5 million plus (or minus if negative) (a) one-half of the aggregate consolidated net income for the period beginning on April 1, 2014 and ending on the date of determination and (b) the amount of net cash proceeds received from the sale of capital stock after June 2, 2014 and ending on the date of determination less (c) cash dividends and share repurchases after June 2, 2014
Restricted payment	$ 120,600
Brazil Credit Facilities [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Amount Outstanding	18,300
FMCC Facility [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity under line of credit facility	$ 300,000
Debt Instrument, Basis Spread on Variable Rate	1.50%
Line of Credit Facility, Fair Value of Amount Outstanding	$ 164,100
Available amount under borrowing capacity	$ 135,900
Cancellation of agreement	30 days
Debt interest rate	5.75%
Revolving Credit Facility, Floorplan Line [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity under line of credit facility	$ 1,750,000
Commitment fees, Percentage	0.15%
Maximum period for outstanding borrowing	1 year
Line of Credit Facility, Amount Outstanding	$ 1,147,100
Available amount under borrowing capacity	292,900
Floorplan Offset	$ (55,600)
Weighted average interest rate	0.00%	2.00%
Revolving Credit Facility, Floorplan Line, New Vehicles [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.25%
Revolving Credit Facility, Floorplan Line, Used Vehicles [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.50%
Revolving Credit Facility, Acquisition Line [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity under line of credit facility	$ 360,000
Line Of Credit Facility, Minimum Borrowing Capacity	$ 50,000
Debt Instrument, Basis Spread on Variable Rate	1.50%
Line of Credit Facility, Amount Outstanding	$ 32,509	$ 0
Available amount under borrowing capacity	298,800
Letters of credit outstanding	29,300
Rental Vehicle Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Amount Outstanding	112,500
UK Credit Facilities [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Amount Outstanding	$ 126,100
Minimum [Member] | Brazil Credit Facilities [Member]
Line of Credit Facility [Line Items]
Debt interest rate	14.67%
Debt Instrument Maturity Date Period	1 month
Grace Period for Outstanding Borrowings	0 days
Minimum [Member] | Revolving Credit Facility, Acquisition Line [Member]
Line of Credit Facility [Line Items]
Commitment fees, Percentage	0.20%
Minimum [Member] | UK Credit Facilities [Member]
Line of Credit Facility [Line Items]
Debt interest rate	1.25%
Maximum [Member] | Brazil Credit Facilities [Member]
Line of Credit Facility [Line Items]
Debt interest rate	19.70%
Debt Instrument Maturity Date Period	12 months
Grace Period for Outstanding Borrowings	90 days
Maximum [Member] | Revolving Credit Facility, Acquisition Line [Member]
Line of Credit Facility [Line Items]
Commitment fees, Percentage	0.45%
Maximum [Member] | Rental Vehicle Credit Facility [Member]
Line of Credit Facility [Line Items]
Debt interest rate	5.75%
Debt Instrument Maturity Date Period	2 years
Maximum [Member] | UK Credit Facilities [Member]
Line of Credit Facility [Line Items]
Debt interest rate	3.95%
United States of America, Dollars | Minimum [Member] | Revolving Credit Facility, Acquisition Line [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.00%
United States of America, Dollars | Maximum [Member] | Revolving Credit Facility, Acquisition Line [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.00%
Euros or Pound Sterling [Member] | Revolving Credit Facility, Acquisition Line [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity under line of credit facility	$ 125,000
Euros or Pound Sterling [Member] | Minimum [Member] | Revolving Credit Facility, Acquisition Line [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.25%
Euros or Pound Sterling [Member] | Maximum [Member] | Revolving Credit Facility, Acquisition Line [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.50%