Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Operating revenues	$ 590,214	$ 618,264	$ 1,751,876	$ 1,841,914
Operating expenses:
Salaries, wages and benefits	197,151	209,586	598,129	618,386
Fuel	37,933	59,518	117,381	176,720
Supplies and maintenance	44,015	46,907	133,079	136,963
Taxes and licenses	24,032	24,244	70,835	70,788
Insurance and claims	23,307	21,930	85,160	65,631
Depreciation	62,980	62,620	199,487	184,816
Rent and purchased transportation	131,843	134,797	378,989	413,809
Communications and utilities	3,797	3,892	11,141	11,806
Other	3,053	1,413	11,688	3,177
Total operating expenses	528,111	564,907	1,605,889	1,682,096
Operating income	62,103	53,357	145,987	159,818
Other expense (income):
Interest expense	887	2,408	3,639	4,695
Interest income	(323)	(756)	(1,326)	(2,648)
Other	55	47	123	(11)
Total other expense (income)	619	1,699	2,436	2,036
Income before income taxes	61,484	51,658	143,551	157,782
Income taxes	15,152	12,614	35,029	39,334
Net income	$ 46,332	$ 39,044	$ 108,522	$ 118,448
Earnings per share:
Basic	$ 0.67	$ 0.56	$ 1.57	$ 1.70
Diluted	$ 0.67	$ 0.56	$ 1.56	$ 1.69
Weighted-average common shares outstanding:
Basic	69,097	69,198	69,148	69,684
Diluted	69,449	69,600	69,500	70,053