Consolidated Statements of Income and Comprehensive Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenues:
Revenue	$ 1,183,257
Lease and rental	57,524	$ 51,244
Total revenue	1,240,781	1,044,797
Cost of products sold:
Lease and rental	48,428	44,304
Total cost of products sold	1,013,786	856,890
Gross profit	226,995	187,907
Selling, general and administrative expense	171,670	150,403
Depreciation and amortization expense	22,908	12,492
Loss on sale of assets	(28)	(163)
Operating income	32,389	24,849
Interest expense, net	4,306	2,791
Income before taxes	28,083	22,058
Provision for income taxes	7,044	7,579
Net income	$ 21,039	$ 14,479
Earnings per common share:
Basic (in dollars per share)	$ 0.53	$ 0.37
Diluted (in dollars per share)	$ 0.51	$ 0.36
Weighted average shares outstanding:
Basic (in shares)	39,665	39,409
Diluted (in shares)	41,092	40,701
Comprehensive income	$ 21,039	$ 14,479
New and Used Commercial Vehicle [Member]
Revenues:
Revenue	773,100	635,953
Cost of products sold:
Cost of products sold	710,914	588,120
Parts and Service [Member]
Revenues:
Revenue	400,295	350,106
Cost of products sold:
Cost of products sold	254,444	224,466
Finance and Insurance [Member]
Revenues:
Revenue	4,741	3,929
Product and Service, Other [Member]
Revenues:
Revenue	$ 5,121	$ 3,565