Condensed Consolidated Financial Information Condensed Consolidated Cash Flow (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013
Net Cash Provided by (Used in) Operating Activities	$ 58,167	$ 133,192
Payments to Acquire Businesses, Net of Cash Acquired	(50,142)	(52,648)
Proceeds from disposition of franchises, property and equipment	1,171	197
Payments to Acquire Property, Plant, and Equipment	(23,157)	(27,095)
Payments for (Proceeds from) Other Investing Activities	287	(1,539)
Net cash provided by (used in) investing activities	(71,841)	(81,085)
Borrowings on credit facility - Floorplan Line	1,597,034	1,503,650
Repayments On Credit Facility - Floorplan Line	(1,641,072)	(1,511,811)
Borrowings on Credit Facility - Acquisition Line	189,933	19,963
Repayments on Credit Facility - Acquisition Line	(135,907)	(30,000)
Borrowings On Real Estate Credit Facility	0	200
Principal Payments On Real Estate Credit Facility	(836)	(677)
Proceeds from Issuance of Other Long-term Debt	13,678	19,683
Repayments of Other Long-term Debt	(10,644)	(24,321)
Borrowings Of Long Term Debt Related To Real Estate Loans	17,600	13,855
Principal Payments Of Long Term Debt Related To Real Estate Loans	(5,622)	(11,510)
Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Including Stock Options	(2,140)	(1,089)
Payments for Repurchase of Common Stock	(16,175)	(16,942)
Excess Tax Benefit from Share-based Compensation, Financing Activities	1,004	733
Payments of Ordinary Dividends, Common Stock	(4,892)	(4,115)
Borrowings (repayments) with subsidiaries	0	0
Change in investment in subsidiaries	0	0
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	0	0
Investment in Subsidiaries	0		0
Net cash provided by (used in) financing activities	1,961	(42,381)
Effect of Exchange Rate on Cash and Cash Equivalents	(2,983)	(12,254)
Cash and Cash Equivalents, Period Increase (Decrease)	(14,696)	(2,528)
Cash and Cash Equivalents, at Carrying Value	26,279	17,687	40,975	20,215
Parent Company [Member]
Net Cash Provided by (Used in) Operating Activities	(399)	(173)
Payments to Acquire Businesses, Net of Cash Acquired	0	0
Proceeds from disposition of franchises, property and equipment	0	0
Payments to Acquire Property, Plant, and Equipment	0	0
Payments for (Proceeds from) Other Investing Activities	0	0
Net cash provided by (used in) investing activities	0	0
Borrowings on credit facility - Floorplan Line	0	0
Repayments On Credit Facility - Floorplan Line	0	0
Borrowings on Credit Facility - Acquisition Line	189,933	19,963
Repayments on Credit Facility - Acquisition Line	(135,907)	(30,000)
Borrowings On Real Estate Credit Facility		0
Principal Payments On Real Estate Credit Facility	0	0
Proceeds from Issuance of Other Long-term Debt	0	0
Repayments of Other Long-term Debt	0	0
Borrowings Of Long Term Debt Related To Real Estate Loans	0	0
Principal Payments Of Long Term Debt Related To Real Estate Loans	0	0
Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Including Stock Options	(2,140)	(1,089)
Payments for Repurchase of Common Stock	(16,175)	(16,942)
Excess Tax Benefit from Share-based Compensation, Financing Activities	0	0
Payments of Ordinary Dividends, Common Stock	(4,892)	(4,115)
Borrowings (repayments) with subsidiaries	9,831	77,862
Change in investment in subsidiaries	(40,251)	(45,506)
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	0	0
Investment in Subsidiaries	2,039,365		1,964,442
Net cash provided by (used in) financing activities	399	173
Effect of Exchange Rate on Cash and Cash Equivalents	0	0
Cash and Cash Equivalents, Period Increase (Decrease)	0	0
Cash and Cash Equivalents, at Carrying Value	0	0	0	0
Guarantor Subsidiaries [Member]
Net Cash Provided by (Used in) Operating Activities	57,971	129,876
Payments to Acquire Businesses, Net of Cash Acquired	(50,142)	(52,648)
Proceeds from disposition of franchises, property and equipment	816	0
Payments to Acquire Property, Plant, and Equipment	(16,949)	(24,552)
Payments for (Proceeds from) Other Investing Activities	287	(1,539)
Net cash provided by (used in) investing activities	(65,988)	(78,739)
Borrowings on credit facility - Floorplan Line	1,597,034	1,503,650
Repayments On Credit Facility - Floorplan Line	(1,641,072)	(1,511,811)
Borrowings on Credit Facility - Acquisition Line	0	0
Repayments on Credit Facility - Acquisition Line	0	0
Borrowings On Real Estate Credit Facility		200
Principal Payments On Real Estate Credit Facility	(836)	(677)
Proceeds from Issuance of Other Long-term Debt	0	0
Repayments of Other Long-term Debt	0	0
Borrowings Of Long Term Debt Related To Real Estate Loans	0	13,855
Principal Payments Of Long Term Debt Related To Real Estate Loans	(5,102)	(3,939)
Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Including Stock Options	0	0
Payments for Repurchase of Common Stock	0	0
Excess Tax Benefit from Share-based Compensation, Financing Activities	1,004	733
Payments of Ordinary Dividends, Common Stock	0	0
Borrowings (repayments) with subsidiaries	9,239	(99,669)
Change in investment in subsidiaries	26,820	45,656
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	0	0
Investment in Subsidiaries	0		0
Net cash provided by (used in) financing activities	(12,913)	(52,002)
Effect of Exchange Rate on Cash and Cash Equivalents	0	0
Cash and Cash Equivalents, Period Increase (Decrease)	(20,930)	(865)
Cash and Cash Equivalents, at Carrying Value	4,449	3,441	25,379	4,306
Non-Guarantor Subsidiaries [Member]
Net Cash Provided by (Used in) Operating Activities	595	3,489
Payments to Acquire Businesses, Net of Cash Acquired	0	0
Proceeds from disposition of franchises, property and equipment	355	197
Payments to Acquire Property, Plant, and Equipment	(6,208)	(2,543)
Payments for (Proceeds from) Other Investing Activities	0	0
Net cash provided by (used in) investing activities	(5,853)	(2,346)
Borrowings on credit facility - Floorplan Line	0	0
Repayments On Credit Facility - Floorplan Line	0	0
Borrowings on Credit Facility - Acquisition Line	0	0
Repayments on Credit Facility - Acquisition Line	0	0
Borrowings On Real Estate Credit Facility		0
Principal Payments On Real Estate Credit Facility	0	0
Proceeds from Issuance of Other Long-term Debt	13,678	19,683
Repayments of Other Long-term Debt	(10,644)	(24,321)
Borrowings Of Long Term Debt Related To Real Estate Loans	17,600	0
Principal Payments Of Long Term Debt Related To Real Estate Loans	(520)	(7,571)
Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Including Stock Options	0	0
Payments for Repurchase of Common Stock	0	0
Excess Tax Benefit from Share-based Compensation, Financing Activities	0	0
Payments of Ordinary Dividends, Common Stock	0	0
Borrowings (repayments) with subsidiaries	(19,070)	21,807
Change in investment in subsidiaries	13,431	(150)
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	0	0
Investment in Subsidiaries	0		0
Net cash provided by (used in) financing activities	14,475	9,448
Effect of Exchange Rate on Cash and Cash Equivalents	(2,983)	(12,254)
Cash and Cash Equivalents, Period Increase (Decrease)	6,234	(1,663)
Cash and Cash Equivalents, at Carrying Value	21,830	14,246	15,596	15,909
Consolidation, Eliminations [Member]
Investment in Subsidiaries	(2,039,365)		(1,964,442)
Cash and Cash Equivalents, at Carrying Value	$ 0		$ 0