Consolidated Statements of Comprehensive Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Income Statement [Abstract]
Operating Revenue	$ 224,481	$ 134,273
Operating Expenses
Salaries, wages, and benefits	70,945	40,598
Rent and purchased transportation	14,510	1,298
Fuel	63,225	42,978
Operations and maintenance	10,121	5,441
Operating taxes and licenses	4,846	2,416
Insurance and claims	7,095	2,860
Communications and utilities	1,830	774
Depreciation and amortization	24,573	15,066
Other operating expenses	8,691	3,813
Gain on disposal of property and equipment	(2,043)	(11,178)
Total operating expenses	203,793	104,066
Operating income	20,688	30,207
Interest income	36	123
Interest Expense	(155)	0
Income before income taxes	20,569	30,330
Federal and state income taxes	6,490	10,596
Net income	14,079	19,734
Other comprehensive income, net of tax	0	0
Comprehensive income	$ 14,079	$ 19,734
Net income per share
Basic	$ 0.16	$ 0.23
Diluted	$ 0.16	$ 0.23
Weighted average shares outstanding
Basic	87,704	84,770
Diluted	87,917	85,046
Dividends declared per share	$ 0.02	$ 0.02