Consolidated Statements of Comprehensive Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Operating Revenue	$ 134,833	$ 127,692
Operating Expenses
Salaries, wages, and benefits	41,996	42,201
Rent and purchased transportation	1,662	1,937
Fuel	42,705	39,147
Operations and maintenance	5,652	5,097
Operating taxes and licenses	2,075	2,307
Insurance and claims	2,514	2,494
Communications and utilities	747	644
Depreciation	13,939	12,378
Other operating expenses	3,979	3,482
Gain on disposal of property and equipment	(4,214)	(3,868)
Total operating expenses	111,055	105,819
Operating income	23,778	21,873
Interest income	142	237
Income before income taxes	23,920	22,110
Federal and state income taxes	7,332	7,231
Net income	16,588	14,879
Other comprehensive income	0	0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 16,588	$ 14,879
Earnings per share
Basic	$ 0.19	$ 0.16
Diluted	$ 0.19	$ 0.16
Weighted average shares outstanding
Basic	86,475	90,689
Diluted	86,826	90,689
Dividends declared per share	$ 0.02	$ 0.02