Consolidated Statements of Income and Comprehensive Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues
Revenue	$ 1,120,655	$ 1,536,316	$ 3,291,759	$ 4,308,170
Lease and rental	57,913	62,949	175,984	183,973
Total revenue	1,178,568	1,599,265	3,467,743	4,492,143
Cost of products sold
Lease and rental	49,545	52,223	153,244	153,316
Total cost of products sold	966,116	1,334,497	2,828,459	3,700,953
Gross profit	212,452	264,768	639,284	791,190
Selling, general and administrative expense	155,487	192,482	496,756	573,644
Depreciation and amortization expense	14,423	14,033	43,269	40,552
Gain (loss) on sale of assets	326	70	1,807	(12)
Operating income	42,868	58,323	101,066	176,982
Other income	2,113	1,577	5,074	2,316
Interest expense, net	1,053	7,690	8,031	23,120
Income before taxes	43,928	52,210	98,109	156,178
Income tax provision	9,989	13,106	24,247	38,349
Net income	$ 33,939	$ 39,104	$ 73,862	$ 117,829
Earnings per common share:
Basic (in dollars per share)	$ 0.62	$ 0.71	$ 1.35	$ 2.14
Diluted (in dollars per share)	$ 0.60	$ 0.70	$ 1.32	$ 2.09
Weighted average shares outstanding:
Basic (in shares)	55,033	54,817	54,734	55,116
Diluted (in shares)	56,443	56,026	55,929	56,438
Dividends declared per common share (in dollars per share)	$ 0.14	$ 0.13	$ 0.40	$ 0.37
Comprehensive income	$ 34,427	$ 39,159	$ 73,345	$ 117,763
New and Used Commercial Vehicle [Member]
Revenues
Revenue	711,754	1,070,868	2,060,370	2,933,952
Cost of products sold
Cost of products sold	658,192	997,946	1,908,225	2,717,484
Parts and Service [Member]
Revenues
Revenue	400,260	454,785	1,205,791	1,341,305
Cost of products sold
Cost of products sold	258,379	284,328	766,990	830,153
Finance and Insurance [Member]
Revenues
Revenue	5,633	5,863	15,060	18,874
Product and Service, Other [Member]
Revenues
Revenue	$ 3,008	$ 4,800	$ 10,538	$ 14,039