Result of Operations by Segments (Detail) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Segment Reporting Information [Line Items]
Gross revenues	$ 71,856,000	$ 85,359,000	$ 202,853,000	$ 247,803,000	$ 320,000,000
Purchased transportation	56,251,000	69,740,000	161,313,000	202,528,000
Purchased equipment for resale	818,000		1,101,000
Commissions	9,308,000	10,906,000	25,667,000	32,693,000
Operating expenses	3,164,000	3,062,000	9,126,000	8,098,000
Income from operations	2,315,000	1,651,000	5,646,000	4,484,000	6,400,000
Interest expense	75,000	119,000	247,000	403,000
Income taxes	850,000	588,000	2,094,000	1,572,000
Net income	1,390,000	944,000	3,305,000	2,509,000	3,600,000
Assets	62,691,000	69,510,000	62,691,000	69,510,000	59,107,000
Transportation services
Segment Reporting Information [Line Items]
Gross revenues	70,596,000	85,262,000	201,126,000	246,643,000
Purchased transportation	56,251,000	69,740,000	161,313,000	202,528,000
Commissions	9,308,000	10,906,000	25,667,000	32,693,000
Operating expenses	3,096,000	3,000,000	8,921,000	7,905,000
Income from operations	1,941,000	1,616,000	5,225,000	3,517,000
Interest expense	75,000	119,000	247,000	403,000
Income taxes	708,000	574,000	1,930,000	1,195,000
Net income	1,158,000	923,000	3,048,000	1,919,000
Assets	53,614,000	63,971,000	53,614,000	63,971,000
Agent support services
Segment Reporting Information [Line Items]
Gross revenues	1,260,000	97,000	1,727,000	1,160,000
Purchased equipment for resale	818,000		1,101,000
Operating expenses	68,000	62,000	205,000	193,000
Income from operations	374,000	35,000	421,000	967,000
Income taxes	142,000	14,000	164,000	377,000
Net income	232,000	21,000	257,000	590,000
Assets	$ 9,077,000	$ 5,539,000	$ 9,077,000	$ 5,539,000