Consolidated Condensed Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating revenue	$ 287,281	$ 223,046
Operating expenses (income):
Salaries, wages and benefits	89,349	72,998
Purchased transportation	57,310	40,765
Fuel and fuel taxes	44,368	28,937
Supplies and maintenance	12,313	11,015
Depreciation	26,143	25,687
Operating taxes and licenses	2,640	2,712
Insurance and claims	12,704	11,446
Communications and utilities	2,265	2,083
Other	8,871	5,389
Total operating expenses	251,423	199,048
Operating income	35,858	23,998
Other	(7)	(10)
Income before income taxes	35,865	24,008
Income taxes expense	8,332	6,002
Net income	$ 27,533	$ 18,006
Basic earnings per common share (in dollars per share)	$ 0.33	$ 0.22
Diluted earnings per common share (in dollars per share)	0.33	0.22
Dividends declared per common share (in dollars per share)	$ 0.06	$ 0.04
Revenue Equipment [Member]
Operating expenses (income):
Gain on disposition of property, plant and equipment	$ (4,540)	$ (1,984)