Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating revenues	$ 501,221	$ 482,802
Operating expenses:
Salaries, wages and benefits	160,839	156,737
Fuel	45,156	32,060
Supplies and maintenance	38,232	47,115
Taxes and licenses	20,786	20,987
Insurance and claims	19,840	18,347
Depreciation	55,336	50,164
Rent and purchased transportation	126,425	117,976
Communications and utilities	4,072	3,909
Other	4,563	3,020
Total operating expenses	475,249	450,315
Operating income	25,972	32,487
Other expense (income):
Interest expense	776	494
Interest income	(914)	(990)
Other	53	45
Total other income	(85)	(451)
Income before income taxes	26,057	32,938
Income taxes	10,038	12,846
Net income	$ 16,019	$ 20,092
Earnings per share:
Basic	$ 0.22	$ 0.28
Diluted	0.22	0.28
Dividends declared per share	$ 0.060	$ 0.060
Weighted-average common shares outstanding:
Basic	72,191	72,025
Diluted	72,447	72,353