Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Revenues:
Sales revenue	$ 1,078,106	$ 903,080
Cost of sales:
Cost of revenue	906,045	756,642
Gross profit	172,061	146,438
Selling, general and administrative	121,829	101,131
Depreciation and amortization	5,507	4,721
Operating income	44,725	40,586
Floor plan interest expense	(2,984)	(3,449)
Other interest expense	(1,974)	(2,361)
Other income, net	937	801
Income from continuing operations before income taxes	40,704	35,577
Income tax provision	(16,010)	(13,695)
Income from continuing operations, net of income tax	24,694	21,882
Income from discontinued operations, net of income tax	40	173
Net income	24,734	22,055
Basic income per share from continuing operations (in Dollars per share)	$ 0.95	$ 0.85
Basic income per share from discontinued operations (in Dollars per share)		$ 0.01
Basic net income per share (in Dollars per share)	$ 0.95	$ 0.86
Shares used in basic per share calculations (in Shares)	25,973	25,626
Diluted income per share from continuing operations (in Dollars per share)	$ 0.94	$ 0.84
Diluted income per share from discontinued operations (in Dollars per share)		$ 0.01
Diluted net income per share (in Dollars per share)	$ 0.94	$ 0.85
Shares used in diluted per share calculations (in Shares)	26,320	26,054
New Vehicle [Member]
Revenues:
Sales revenue	579,522	493,441
Cost of sales:
Cost of revenue	540,498	458,794
Used Retail Vehicle [Member]
Revenues:
Sales revenue	301,893	239,228
Cost of sales:
Cost of revenue	261,097	204,255
Used Wholesale Vehicle [Member]
Revenues:
Sales revenue	42,693	39,506
Cost of sales:
Cost of revenue	41,362	38,532
Finance and Insurance [Member]
Revenues:
Sales revenue	39,631	31,663
Service, Body and Parts [Member]
Revenues:
Sales revenue	104,617	90,440
Cost of sales:
Cost of revenue	53,785	46,661
Fleet and Other [Member]
Revenues:
Sales revenue	9,750	8,802
Cost of sales:
Cost of revenue	$ 9,303	$ 8,400