Consolidated Statements of Income and Comprehensive Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenues:
New and used commercial vehicle sales	$ 775,988	$ 636,853	$ 1,411,941	$ 1,305,398
Aftermarket products and services sales	366,599	328,665	716,705	670,604
Lease and rental sales	53,048	52,152	104,292	103,039
Finance and insurance	4,392	4,837	8,321	9,336
Other	3,496	3,955	7,061	8,925
Total revenue	1,203,523	1,026,462	2,248,320	2,097,302
Cost of products sold:
New and used commercial vehicle sales	718,253	591,331	1,306,373	1,214,991
Aftermarket products and services sales	231,992	209,519	456,458	427,762
Lease and rental sales	44,206	45,134	88,510	90,801
Total cost of products sold	994,451	845,984	1,851,341	1,733,554
Gross profit	209,072	180,478	396,979	363,748
Selling, general and administrative expense	159,353	146,080	309,756	308,532
Depreciation and amortization expense	12,444	12,821	24,936	25,468
Gain (loss) on sale of assets	132	(5)	(31)	5
Operating income	37,407	21,572	62,256	29,753
Interest expense, net	2,824	3,763	5,615	8,002
Income before taxes	34,583	17,809	56,641	21,751
Provision for income taxes	12,584	6,992	20,163	8,539
Net income	$ 21,999	$ 10,817	$ 36,478	$ 13,212
Earnings per common share:
Basic (in dollars per share)	$ 0.55	$ 0.27	$ 0.92	$ 0.33
Diluted (in dollars per share)	$ 0.54	$ 0.27	$ 0.90	$ 0.32
Weighted average shares outstanding:
Basic (in shares)	39,641	40,250	39,493	40,402
Diluted (in shares)	40,839	40,778	40,737	40,914
Comprehensive income	$ 22,285	$ 10,828	$ 36,764	$ 13,223