Note 4 - Segment Reporting (Detail) - Base Revenue and Fuel Surcharge Revenue by Segments (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012
Base revenue
Base Revenue	$ 104,887	$ 97,823
Fuel surcharge revenue
Fuel Surcharge Revenue	27,140	25,850
Total revenue	132,027	123,673
Trucking [Member]
Base revenue
Base Revenue	79,803	75,937
Fuel surcharge revenue
Fuel Surcharge Revenue	22,225	21,031
SCS [Member]
Base revenue
Base Revenue	23,043	22,318
Fuel surcharge revenue
Fuel Surcharge Revenue	4,320	4,026
Intermodal [Member]
Base revenue
Base Revenue	3,744	4,406
Fuel surcharge revenue
Fuel Surcharge Revenue	1,057	1,302
Intersegment Elimination [Member]
Base revenue
Base Revenue	(1,703)	(4,838)
Fuel surcharge revenue
Fuel Surcharge Revenue	$ (462)	$ (509)

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- Definition

Revenue from transporting cargo and freight between locations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1(d))

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Audit and Accounting Guide (AAG)

-Number AAG-AIR

-Paragraph 4

-IssueDate 2003-05-01

-Chapter 3

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

Repayment received or receivable for expenses incurred on behalf of a client or customer, other than those reimbursements received by landlords from tenants.

+ References

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- Definition

Aggregate revenue recognized during the period (derived from goods sold, services rendered, insurance premiums, or other activities that constitute an entity's earning process). For financial services companies, also includes investment and interest income, and sales and trading gains.

+ References

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