Consolidated Condensed Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Operating revenue	$ 298,023	$ 287,281
Operating expenses (income):
Salaries, wages and benefits	98,516	89,349
Purchased transportation	54,103	57,310
Fuel and fuel taxes	46,796	44,368
Supplies and maintenance	15,987	12,313
Depreciation	29,530	26,143
Operating taxes and licenses	2,768	2,640
Insurance and claims	15,070	12,704
Communications and utilities	2,531	2,265
Other	8,958	8,871
Total operating expenses	269,013	251,423
Operating income	29,010	35,858
Other	(844)	(7)
Income before income taxes	29,854	35,865
Income taxes expense	7,352	8,332
Net income	$ 22,502	$ 27,533
Basic earnings per common share (in dollars per share)	$ 0.28	$ 0.33
Diluted earnings per common share (in dollars per share)	0.28	0.33
Dividends declared per common share (in dollars per share)	$ 0.06	$ 0.06
Revenue Equipment [Member]
Operating expenses (income):
Gain on disposition of revenue equipment	$ (5,246)	$ (4,540)