Consolidated Statements of Income and Comprehensive Income (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Revenues:
New and used truck sales	$ 508,194	$ 598,220	$ 997,804	$ 1,150,148
Parts and service	242,928	208,290	474,407	404,936
Lease and rental	31,358	23,433	61,498	46,909
Finance and insurance	3,838	3,577	6,971	6,714
Other	3,356	2,324	5,782	4,466
Total revenue	789,674	835,844	1,546,462	1,613,173
Cost of products sold:
New and used truck sales	473,153	559,017	925,727	1,069,824
Parts and service	152,449	127,617	298,162	245,873
Lease and rental	26,384	19,574	51,097	39,580
Total cost of products sold	651,986	706,208	1,274,986	1,355,277
Gross profit	137,688	129,636	271,476	257,896
Selling, general and administrative	118,628	91,683	220,734	184,698
Depreciation and amortization	7,259	6,055	14,369	11,939
(Loss) gain on sale of assets	(12)	68	29	87
Operating income	11,789	31,966	36,402	61,346
Interest expense, net	2,480	3,407	4,993	6,711
Income before taxes	9,309	28,559	31,409	54,635
Provision for income taxes	3,677	11,137	12,230	21,307
Net income	5,632	17,422	19,179	33,328
Earnings per common share:
Basic (in Dollars per share)	$ 0.14	$ 0.45	$ 0.49	$ 0.86
Diluted (in Dollars per share)	$ 0.14	$ 0.44	$ 0.47	$ 0.84
Weighted average shares outstanding:
Basic (in Shares)	39,552	38,675	39,337	38,531
Diluted (in Shares)	40,581	39,544	40,446	39,605
Comprehensive income	$ 5,785	$ 17,428	$ 19,502	$ 33,333