Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating revenues	$ 596,117	$ 562,684
Operating expenses:
Salaries, wages and benefits	202,799	182,794
Fuel	56,138	59,032
Supplies and maintenance	45,685	45,739
Taxes and licenses	22,901	22,493
Insurance and claims	22,709	21,158
Depreciation	60,759	55,506
Rent and purchased transportation	132,836	135,922
Communications and utilities	4,011	4,107
Other	260	818
Total operating expenses	548,098	527,569
Operating income	48,019	35,115
Other expense (income):
Interest expense	858	482
Interest income	(903)	(740)
Other	(116)	53
Total other expense (income)	(161)	(205)
Income before income taxes	48,180	35,320
Income taxes	12,094	7,513
Net income	$ 36,086	$ 27,807
Earnings per share:
Basic	$ 0.51	$ 0.38
Diluted	$ 0.51	$ 0.38
Weighted-average common shares outstanding:
Basic	70,274	72,435
Diluted	70,572	72,671