Note 1 - Significant Accounting Policies (Details Textual) $ / shares in Units, shares in Millions	3 Months Ended											9 Months Ended	12 Months Ended
	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($) $ / shares	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	[1]	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)		Mar. 31, 2015 USD ($)	[3]	Sep. 30, 2016	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	May 31, 2011
Number of Reportable Segments													1
Number of Asset-based Operating Fleets Aggregated in a Segment													3
Revenues	$ 190,978,000	$ 164,500,000	$ 158,832,000	$ 156,341,000		$ 208,061,000	$ 173,512,000	$ 175,451,000	[2]	$ 167,216,000			$ 670,651,000	$ 724,240,000	$ 718,980,000
Accounts Receivable, Net, Current	96,636,000					112,669,000							96,636,000	112,669,000
Allowance for Doubtful Accounts Receivable	1,345,000					1,857,000							1,345,000	1,857,000	1,767,000	$ 1,736,000
Finite-Lived Intangible Assets, Net	0					169,000							0	169,000
Insurance Policy Primary Occurence Limit	1,000,000												1,000,000
Workers Compensation Self Insurance Per Claim													1,300,000
Cargo Losses Purchased Coverage per Claim													300,000
Employee Annual Insuarnce Deductible Per Claim													$ 400,000
Physical Damage Coverage													100.00%
Drivers Advances And Other Receivables Net Of Allowance	8,757,000					8,779,000							$ 8,757,000	8,779,000
Liability for Claims and Claims Adjustment Expense	20,000,000												20,000,000
Reduction in Insurance and Claims Expense								$ 3,600,000
Liability for Claims and Claims Adjustment Expense, Single Loss Limit	9,000,000												9,000,000
Liability for Claims and Claims Adjustment Expense, Aggregate Limit per Policy Year	18,000,000												18,000,000
Liability for Claims and Claims Adjustment Expense, Aggregate Three Year Limit	30,000,000												30,000,000
Auto Policy Release Premium Refund													13,600,000
Interest Costs Capitalized													$ 100,000	100,000	100,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | shares													0.1
Prior Period Reclassification Adjustment													$ 2,247,000
Goodwill	$ 0					0							0	0
Reclassification of Debt Issuance Costs from Other Assets to Long-term Notes Payable [Member] | December 31, 2015 [Member]
Prior Period Reclassification Adjustment													700,000
Accounting Standards Update 2016-09 [Member]
Current Period Reclassification Adjustment													2,200,000
Income Tax Benefit, Previously Unrecognized Tax Benefits													$ 1,100,000
Tractors [Member]
Property, Plant and Equipment, Useful Life													5 years
Property, Plant and Equipment, Salvage Value, Percentage	15.00%												15.00%
Tractors [Member] | Salvage Value [Member]
Depreciation, Additional Expense	$ 2,000,000	2,000,000
Depreciation, Additional Expense, After Tax	$ 1,200,000	$ 1,200,000
Effect of Additional Depreciation Expense on Earnings Per Share | $ / shares		$ (0.06)
Refrigerated Trailers [Member]
Property, Plant and Equipment, Useful Life													7 years
Dry Van Trailers [Member]
Property, Plant and Equipment, Useful Life													10 years
Property, Plant and Equipment, Salvage Value, Percentage	25.00%												25.00%
Collateral for Collection Issues [Member]
Accounts Payable	$ 300,000												$ 300,000
Minimum [Member]
Cash Advance For Factoring Receivables Percentage													85.00%
Finite-Lived Intangible Asset, Useful Life													4 years
Minimum [Member] | Revenue Equipment [Member]
Property, Plant and Equipment, Useful Life													3 years
Capital Leases of Lessee, Term of Contract												5 years	5 years
Maximum [Member]
Cash Advance For Factoring Receivables Percentage													95.00%
Finite-Lived Intangible Asset, Useful Life													20 years
Maximum [Member] | Revenue Equipment [Member]
Property, Plant and Equipment, Useful Life													10 years
Capital Leases of Lessee, Term of Contract												7 years	7 years
Wal-Mart [Member]
Revenues													$ 69,400,000
UPS (United Parcel Service) [Member]
Revenues														$ 75,800,000	$ 82,600,000
Customer Concentration Risk [Member] | Sales Revenue, Net [Member]
Concentration Risk, Percentage													53.00%	45.00%	38.00%
Number of Major Customers													1	1
Non Asset Operations [Member] | Solutions [Member]
Revenues													$ 2,600,000	$ 2,400,000	$ 2,300,000
Factoring Receivables [Member]
Accounts Receivable, Net, Current	25,800,000					18,900,000							25,800,000	18,900,000
Allowance for Doubtful Accounts Receivable	200,000					200,000							200,000	200,000
Receivables from Insurers [Member]
Drivers Advances And Other Receivables Net Of Allowance	700,000					100,000							700,000	100,000
Self Insurance [Member]
Other Assets	$ 100,000					$ 600,000							$ 100,000	$ 600,000
Transport Enterprise Leasing LLC [Member]
Equity Method Investment, Ownership Percentage	49.00%												49.00%				49.00%

[1] Adjusted from 10-Q as filed due to implementation of ASU 2016-09.

[2] Includes $3.6 million in return of previously expensed insurance premiums for the commutation of our primary auto liability policy for the period of April 1, 2013, through September 30, 2014.

[3] Includes $4.7 million after tax one-time federal income tax credit.