Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues
Revenue	$ 4,878,908	$ 4,499,717	$ 5,562,298
Lease and rental	247,234	236,223	247,549
Total revenue	5,126,142	4,735,940	5,809,847
Cost of products sold
Lease and rental	188,093	202,412	206,200
Total cost of products sold	4,033,844	3,860,473	4,784,219
Gross profit	1,092,298	875,467	1,025,628
Selling, general and administrative	731,340	665,258	753,749
Depreciation and amortization	53,354	57,456	55,372
Gain (loss) on sale of assets	1,432	1,852	(102)
Operating income	309,036	154,605	216,405
Other income	6,417	6,132	1,925
Interest income (expense):
Interest income	657	713	1,680
Interest expense	(2,427)	(9,727)	(30,487)
Total interest expense, net	1,770	9,014	28,807
Income before taxes	313,683	151,723	189,523
Income tax provision	72,268	36,836	47,940
Net income	$ 241,415	$ 114,887	$ 141,583
Earnings per common share
Basic (in dollars per share)	$ 4.32	$ 2.09	$ 2.57
Diluted (in dollars per share)	4.17	2.04	2.51
Dividends declared per common share (in dollars per share)	$ 0.74	$ 0.41	$ 0.34
New and Used Commercial Vehicle [Member]
Revenues
Revenue	$ 3,039,953	$ 2,863,309	$ 3,757,584
Cost of products sold
Cost of products sold	2,736,502	2,641,487	3,480,682
Parts and Service [Member]
Revenues
Revenue	1,793,363	1,600,445	1,762,510
Cost of products sold
Cost of products sold	1,109,249	1,016,574	1,097,337
Finance and Insurance [Member]
Revenues
Revenue	27,964	21,949	24,443
Product and Service, Other [Member]
Revenues
Revenue	$ 17,628	$ 14,014	$ 17,761