Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Sales revenue	$ 903,080	$ 738,246
Cost of revenue	756,642	613,912
Gross profit	146,438	124,334
Asset impairments		115
Selling, general and administrative	101,131	88,439
Operating income	40,586	31,642
Floor plan interest expense	(3,449)	(2,902)
Other interest expense	(2,361)	(2,727)
Other income, net	801	498
Income from continuing operations before income taxes	35,577	26,511
Income tax provision	(13,695)	(9,877)
Income from continuing operations, net of income tax	21,882	16,634
Income from discontinued operations, net of income tax	173	162
Net income	22,055	16,796
Basic income per share from continuing operations (in Dollars per share)	$ 0.85	$ 0.64
Basic income per share from discontinued operations (in Dollars per share)	$ 0.01	$ 0.01
Basic net income per share (in Dollars per share)	$ 0.86	$ 0.65
Shares used in basic per share calculations (in Shares)	25,626	25,986
Diluted income per share from continuing operations (in Dollars per share)	$ 0.84	$ 0.63
Diluted income per share from discontinued operations (in Dollars per share)	$ 0.01
Diluted net income per share (in Dollars per share)	$ 0.85	$ 0.63
Shares used in diluted per share calculations (in Shares)	26,054	26,478
New Vehicle [Member]
Sales revenue	493,441	392,946
Cost of revenue	458,794	362,694
Used Retail Vehicle [Member]
Sales revenue	239,228	190,619
Cost of revenue	204,255	162,342
Used Wholesale Vehicle [Member]
Sales revenue	39,506	33,357
Cost of revenue	38,532	32,960
Finance and Insurance [Member]
Sales revenue	31,663	24,876
Service, Body and Parts [Member]
Sales revenue	90,440	83,544
Cost of revenue	46,661	43,409
Fleet and Other [Member]
Sales revenue	8,802	12,904
Cost of revenue	8,400	12,507
Segment, Continuing Operations [Member]
Depreciation and amortization	$ 4,721	$ 4,138