Interim Financial Information (Details Textual)	3 Months Ended	9 Months Ended
	Sep. 30, 2015 USD ($) dealerships town states	Sep. 30, 2015 USD ($) dealerships town states	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Business And Organization [Line Items]
Number of geographic regions		4
Number of Reportable Segments		3
Immaterial Error of Effect of Exchange Rate on Cash and Cash Equivalents		$ (5,246,000)	$ (563,000)
Net Cash Provided by (Used in) Operating Activities		$ 230,868,000	$ 271,836,000
Number of domestic regions	2	2
Number of international regions	2	2
Variable Interest Entity [Line Items]
Assets, Current	$ 2,044,790,000	$ 2,044,790,000		$ 2,035,219,000
Total assets	4,292,050,000	4,292,050,000		4,141,492,000
Liabilities, Current	$ 1,981,847,000	1,981,847,000		1,922,199,000
Variable Interest Entity, Ownership Percentage	8.00%
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Assets, Current	$ 12,280,000	12,280,000		19,049,000
Long-Lived Assets	20,764,000	20,764,000		31,783,000
Total assets	33,044,000	33,044,000		50,832,000
Liabilities, Current	9,259,000	9,259,000		16,374,000
Liabilities, Noncurrent	15,215,000	15,215,000		15,955,000
Total liabilities	$ 24,474,000	$ 24,474,000		$ 32,329,000
East [Member]
Business And Organization [Line Items]
Number of dealerships | dealerships	40	40
West [Member]
Business And Organization [Line Items]
Number of dealerships | dealerships	77	77
U.S. [Member]
Business And Organization [Line Items]
Number of States in which Entity Operates | states	14	14
U.K. [Member]
Business And Organization [Line Items]
Number of Towns in which Entity Operates | town	15	15
Number of dealerships | dealerships	17	17
Brazil [Member]
Business And Organization [Line Items]
Number of States in which Entity Operates | states	3	3
Number of dealerships | dealerships	19	19