Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Operating revenues	$ 618,264	$ 629,735	$ 1,841,914	$ 1,811,549
Operating expenses:
Salaries, wages and benefits	209,586	201,606	618,386	580,515
Fuel	59,518	67,072	176,720	191,769
Supplies and maintenance	46,907	47,136	136,963	138,556
Taxes and licenses	24,244	18,463	70,788	63,607
Insurance and claims	21,930	22,011	65,631	73,858
Depreciation	62,620	58,382	184,816	170,439
Rent and purchased transportation	134,797	147,870	413,809	435,225
Communications and utilities	3,892	3,993	11,806	12,028
Other	1,413	(184)	3,177	(3,732)
Total operating expenses	564,907	566,349	1,682,096	1,662,265
Operating income	53,357	63,386	159,818	149,284
Other expense (income):
Interest expense	2,408	870	4,695	1,842
Interest income	(756)	(646)	(2,648)	(2,079)
Other	47	41	(11)	172
Total other expense (income)	1,699	265	2,036	(65)
Income before income taxes	51,658	63,121	157,782	149,349
Income taxes	12,614	15,607	39,334	35,764
Net income	$ 39,044	$ 47,514	$ 118,448	$ 113,585
Earnings per share:
Basic	$ 0.56	$ 0.67	$ 1.70	$ 1.58
Diluted	$ 0.56	$ 0.66	$ 1.69	$ 1.57
Weighted-average common shares outstanding:
Basic	69,198	71,436	69,684	72,001
Diluted	69,600	71,752	70,053	72,300