Consolidated Statements of Income and Comprehensive Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Revenues:
New and used truck sales	$ 917,878	$ 797,291	$ 1,718,072	$ 1,398,191
Parts and service	353,268	330,982	690,290	639,956
Lease and rental	49,297	44,057	97,089	85,046
Finance and insurance	5,678	5,256	10,209	9,332
Other	4,182	4,875	8,178	8,603
Total revenue	1,330,303	1,182,461	2,523,838	2,141,128
Cost of products sold:
New and used truck sales	856,274	738,851	1,600,534	1,296,993
Parts and service	222,225	212,016	436,922	410,719
Lease and rental	44,171	38,245	85,127	74,142
Total cost of products sold	1,122,670	989,112	2,122,583	1,781,854
Gross profit	207,633	193,349	401,255	359,274
Selling, general and administrative	161,309	149,260	313,936	283,705
Depreciation and amortization	10,829	9,177	20,823	17,995
Gain (loss) on sale of assets	65	20	(607)	104
Operating income	35,560	34,932	65,889	57,678
Interest expense, net	3,598	2,543	6,539	5,674
Income before taxes	31,962	32,389	59,350	52,004
Provision for income taxes	12,386	12,551	22,993	20,152
Net income	$ 19,576	$ 19,838	$ 36,357	$ 31,852
Earnings per common share:
Basic (in dollars per share)	$ 0.49	$ 0.50	$ 0.91	$ 0.81
Diluted (in dollars per share)	$ 0.48	$ 0.49	$ 0.89	$ 0.78
Weighted average shares outstanding:
Basic (in shares)	40,275	39,751	40,171	39,544
Diluted (in shares)	41,072	40,849	41,029	40,682
Comprehensive income	$ 19,659	$ 20,154	$ 36,512	$ 32,282