Condensed Consolidated Financial Information Condensed Consolidated Income Statement (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Revenues	$ 2,432,854	$ 2,260,863
Cost of Goods and Services Sold	2,068,970	1,922,741
GROSS PROFIT	363,884	338,122
Selling, General and Administrative Expense	271,469	257,558
Depreciation, Depletion and Amortization	11,684	9,925
INCOME FROM OPERATIONS	80,731	70,639
Floor Plan Interest Expense	(9,348)	(10,913)
Interest Expense, Other	(13,911)	(10,513)
INCOME BEFORE INCOME TAXES	57,472	49,213
Income Tax Expense (Benefit)	21,657	17,910
Income (Loss) from Subsidiaries, Net of Tax	0	0
NET INCOME	35,815	31,303
Other Comprehensive Income (Loss), Net of Tax	(35,140)	7,435
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	675	38,738
Parent Company [Member]
Revenues	0	0
Cost of Goods and Services Sold	0	0
GROSS PROFIT	0	0
Selling, General and Administrative Expense	1,231	842
Depreciation, Depletion and Amortization	0	0
INCOME FROM OPERATIONS	(1,231)	(842)
Floor Plan Interest Expense	0	0
Interest Expense, Other	592	565
INCOME BEFORE INCOME TAXES	(639)	(277)
Income Tax Expense (Benefit)	(240)	(103)
Income (Loss) from Subsidiaries, Net of Tax	36,214	31,477
NET INCOME	35,815	31,303
Other Comprehensive Income (Loss), Net of Tax	0	0
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	35,815	31,303
Guarantor Subsidiaries [Member]
Revenues	1,998,500	1,834,627
Cost of Goods and Services Sold	1,684,012	1,544,895
GROSS PROFIT	314,488	289,732
Selling, General and Administrative Expense	227,472	214,658
Depreciation, Depletion and Amortization	10,118	8,626
INCOME FROM OPERATIONS	76,898	66,448
Floor Plan Interest Expense	(8,519)	(8,584)
Interest Expense, Other	(12,723)	(10,264)
INCOME BEFORE INCOME TAXES	55,656	47,600
Income Tax Expense (Benefit)	20,602	16,931
Income (Loss) from Subsidiaries, Net of Tax	0	0
NET INCOME	35,054	30,669
Other Comprehensive Income (Loss), Net of Tax	(4,546)	(780)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	30,508	29,889
Non-Guarantor Subsidiaries [Member]
Revenues	434,354	426,236
Cost of Goods and Services Sold	384,958	377,846
GROSS PROFIT	49,396	48,390
Selling, General and Administrative Expense	42,766	42,058
Depreciation, Depletion and Amortization	1,566	1,299
INCOME FROM OPERATIONS	5,064	5,033
Floor Plan Interest Expense	(829)	(2,329)
Interest Expense, Other	(1,780)	(814)
INCOME BEFORE INCOME TAXES	2,455	1,890
Income Tax Expense (Benefit)	1,295	1,082
Income (Loss) from Subsidiaries, Net of Tax	0	0
NET INCOME	1,160	808
Other Comprehensive Income (Loss), Net of Tax	(30,594)	8,215
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	(29,434)	9,023
Consolidation, Eliminations [Member]
Revenues	0	0
Cost of Goods and Services Sold	0	0
GROSS PROFIT	0	0
Selling, General and Administrative Expense	0	0
Depreciation, Depletion and Amortization	0	0
INCOME FROM OPERATIONS	0	0
Floor Plan Interest Expense	0	0
Interest Expense, Other	0	0
INCOME BEFORE INCOME TAXES	0	0
Income Tax Expense (Benefit)	0	0
Income (Loss) from Subsidiaries, Net of Tax	(36,214)	(31,477)
NET INCOME	(36,214)	(31,477)
Other Comprehensive Income (Loss), Net of Tax	0	0
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	$ (36,214)	$ (31,477)