Condensed Consolidated Statements of Operations (unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
OPERATING REVENUES:
Revenue, before fuel surcharge	$ 80,657	$ 73,700	$ 158,485	$ 148,868
Fuel surcharge	23,751	20,456	45,904	41,443
Total operating revenues	104,408	94,156	204,389	190,311
OPERATING EXPENSES AND COSTS:
Salaries, wages and benefits	43,847	33,764	84,955	65,805
Fuel expense	24,232	27,389	51,202	58,235
Rent and purchased transportation	5,733	6,326	12,117	13,324
Depreciation	9,766	9,307	19,860	18,554
Operating supplies and expenses	8,812	10,118	17,661	19,443
Operating taxes and licenses	1,230	1,240	2,501	2,479
Insurance and claims	3,810	3,260	7,248	6,595
Communications and utilities	519	537	1,120	1,127
Other	1,666	1,223	3,326	2,633
Gain on disposition of equipment	(213)	(280)	(355)	(243)
Total operating expenses and costs	99,402	92,884	199,635	187,952
OPERATING INCOME	5,006	1,272	4,754	2,359
NON-OPERATING INCOME	289	895	573	1,489
INTEREST EXPENSE	(880)	(605)	(1,695)	(1,167)
INCOME BEFORE INCOME TAXES	4,415	1,562	3,632	2,681
FEDERAL AND STATE INCOME TAX EXPENSE:
Current		52		86
Deferred	1,733	575	1,406	986
Total federal and state income tax expense	1,733	627	1,406	1,072
NET INCOME	$ 2,682	$ 935	$ 2,226	$ 1,609
INCOME PER COMMON SHARE:
Basic (in Dollars per share)	$ 0.31	$ 0.11	$ 0.26	$ 0.18
Diluted (in Dollars per share)	$ 0.31	$ 0.11	$ 0.26	$ 0.18
AVERAGE COMMON SHARES OUTSTANDING:
Basic (in Shares)	8,658	8,702	8,673	8,699
Diluted (in Shares)	8,659	8,703	8,675	8,701
DIVIDENDS DECLARED PER COMMON SHARE (in Dollars per share)				$ 1.00