Condensed Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Share data	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Condensed Consolidated Statements of Operations [Abstract]
Operating Revenue	$ 265,901	$ 231,342	$ 508,919	$ 443,566
Operating Expenses:
Salaries, wages and employees' benefits	130,669	121,421	253,409	238,885
Purchased transportation	24,653	22,011	45,719	39,446
Fuel, operating expenses and supplies	76,186	58,380	146,127	114,282
Operating taxes and licenses	9,600	9,173	18,957	18,387
Claims and insurance	7,836	5,411	15,088	10,496
Depreciation and amortization	8,803	9,222	17,376	18,527
Operating gains, net	(102)	(150)	(103)	(206)
Total operating expenses	257,645	225,468	496,573	439,817
Operating Income	8,256	5,874	12,346	3,749
Nonoperating Expenses:
Interest expense	2,955	2,685	5,953	5,758
Other, net	(19)	63	(110)	(252)
Nonoperating expenses, net	2,936	2,748	5,843	5,506
Income (Loss) Before Income Taxes	5,320	3,126	6,503	(1,757)
Income Tax Provision (Benefit)	1,962	1,146	2,432	(514)
Net Income (Loss)	$ 3,358	$ 1,980	$ 4,071	$ (1,243)
Weighted average common shares outstanding - basic	15,791	15,703	15,780	15,700
Weighted average common shares outstanding - diluted	16,188	16,124	16,167	15,700
Basic Earnings (Loss) Per Share	$ 0.21	$ 0.13	$ 0.26	$ (0.08)
Diluted Earnings (Loss) Per Share	$ 0.21	$ 0.12	$ 0.25	$ (0.08)