Consolidated Condensed Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Revenue Equipment [Member]
Operating expenses (income):
Gain on disposition of revenue equipment	$ (1,895)	$ (1,419)	$ (4,843)	$ (3,360)
Facility [Member]
Operating expenses (income):
Gain on disposition of revenue equipment			(3,712)
Operating revenue	$ 171,346	$ 171,550	496,221	$ 499,382
Salaries, wages and benefits	55,129	46,435	154,901	134,834
Purchased transportation	30,756	32,914	88,343	91,783
Fuel and fuel taxes	26,556	39,398	81,313	119,718
Supplies and maintenance	11,351	10,273	32,735	31,059
Depreciation	19,331	17,253	55,469	50,489
Operating taxes and licenses	2,295	1,837	6,185	5,278
Insurance and claims	7,105	6,205	21,973	18,993
Communications and utilities	1,431	1,507	4,347	4,251
Other	4,933	4,105	13,684	11,723
Total operating expenses	156,992	158,508	450,395	464,768
Operating income	14,354	13,042	45,826	34,614
Other	126	(226)	147	(936)
Income before income taxes	14,228	13,268	45,679	35,550
Provision for income taxes	5,818	5,616	18,724	14,685
Net income	$ 8,410	$ 7,652	$ 26,955	$ 20,865
Basic earnings per common share (in dollars per share)	$ 0.25	$ 0.23	$ 0.80	$ 0.63
Diluted earnings per common share (in dollars per share)	0.25	0.23	0.80	0.62
Dividends declared per common share (in dollars per share)	$ 0.025	$ 0.025	$ 0.075	$ 0.075