Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
OPERATING REVENUES:
Operating revenues	$ 119,458	$ 109,405
OPERATING EXPENSES AND COSTS:
Salaries, wages and benefits	28,639	25,904
Operating supplies and expenses	22,671	20,232
Rent and purchased transportation	45,917	43,123
Depreciation	11,623	10,671
Insurance and claims	4,268	4,697
Other	2,581	2,117
Loss (gain) on disposition of equipment	3	(1)
Total operating expenses and costs	115,702	106,743
OPERATING INCOME	3,756	2,662
NON-OPERATING (EXPENSE)/INCOME	(879)	2,052
INTEREST EXPENSE	(1,160)	(977)
INCOME BEFORE INCOME TAXES	1,717	3,737
FEDERAL AND STATE INCOME TAX EXPENSE:
Current	35	67
Deferred	295	1,387
Total federal and state income tax expense	330	1,454
NET INCOME	$ 1,387	$ 2,283
INCOME PER COMMON SHARE:
Basic (in dollars per share)	$ 0.22	$ 0.36
Diluted (in dollars per share)	$ 0.22	$ 0.36
AVERAGE COMMON SHARES OUTSTANDING:
Basic (in shares)	6,168	6,399
Diluted (in shares)	6,264	6,425
Freight Transportation Service [Member]
OPERATING REVENUES:
Operating revenues	$ 99,104	$ 93,603
Fuel Surcharge [Member]
OPERATING REVENUES:
Operating revenues	$ 20,354	$ 15,802