Note 1 - Summary of Significant Accounting Policies (Details Textual) $ in Thousands		12 Months Ended
	Dec. 31, 2023 USD ($)	Dec. 31, 2023 USD ($) shares	Dec. 31, 2022 USD ($) shares	Dec. 31, 2021 USD ($) shares	Apr. 01, 2024 USD ($)	Dec. 01, 2022 USD ($)
Number of Reportable Segments		4
Insurance Policy Primary Occurence Limit	$ 9,000	$ 9,000	$ 7,000
Insurance Policy Excess Coverage	1,000	1,000	3,000
Insurance Policy Excess Coverage	1,000	1,000	3,000
Contract with Customer, Liability, Revenue Recognized		1,100	$ 1,400	$ 400
Accounts Receivable, after Allowance for Credit Loss	142,500	142,500				$ 119,800
Cash, Uninsured Amount	$ 1,500	$ 1,500
Finite-Lived Intangible Asset, Useful Life (Year)	151 months	151 months	138 months
Accrued Liabilities	$ 59,100	$ 59,100	$ 59,100
Employee-related Liabilities	25,900	25,900	24,600
Accrued Purchased Transportation	8,400	8,400	7,800
Workers Compensation Self Insurance Per Claim		1,500
Cargo Losses Purchased Coverage per Claim		300
Employee Annual Insuarnce Deductible Per Claim		$ 400
Physical Damage Coverage		100.00%
Drivers Advances and Other Receivables Net Of Allowance	4,367	$ 4,367	3,798
Interest Costs Capitalized		$ 300	$ 300	$ 100
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures (in shares) | shares		245,000	358,000	217,000
Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares) | shares		0
Shares Issued, Shares, Share-Based Payment Arrangement, after Forfeiture (in shares) | shares		541,000
Share-Based Payment Arrangement, Option [Member]
Shares Issued, Shares, Share-Based Payment Arrangement, after Forfeiture (in shares) | shares			161,000
Employee Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares) | shares		0	104	124,000
Receivables from Insurers [Member]
Drivers Advances and Other Receivables Net Of Allowance	800	$ 800	$ 0
Insurance Settlements Receivable, Current	0	0	700
Insurance Settlements Receivable, Noncurrent	$ 1,300	$ 1,300	$ 0
Maximum [Member]
Finite-Lived Intangible Asset, Useful Life (Year)	17 years	17 years
Minimum [Member]
Finite-Lived Intangible Asset, Useful Life (Year)	3 years	3 years
Tractors [Member]
Property, Plant and Equipment, Useful Life (Year)	5 years	5 years
Property, Plant and Equipment, Salvage Value, Percentage	0.00%	0.00%
Tractors [Member] | Maximum [Member]
Property, Plant and Equipment, Salvage Value, Percentage	35.00%	35.00%
Refrigerated Trailers [Member]
Property, Plant and Equipment, Useful Life (Year)	7 years	7 years
Dry Van Trailers [Member]
Property, Plant and Equipment, Useful Life (Year)	10 years	10 years
Dry Van Trailers [Member] | Maximum [Member]
Property, Plant and Equipment, Salvage Value, Percentage	25.00%	25.00%
Dry Van Trailers [Member] | Minimum [Member]
Property, Plant and Equipment, Salvage Value, Percentage	28.00%	28.00%
Revenue Equipment [Member] | Maximum [Member]
Property, Plant and Equipment, Useful Life (Year)	20 years	20 years
Capital Leases of Lessee, Term of Contract (Month)		84 months
Revenue Equipment [Member] | Minimum [Member]
Property, Plant and Equipment, Useful Life (Year)	2 years	2 years
Capital Leases of Lessee, Term of Contract (Month)		48 months
Customer Concentration Risk [Member] | Revenue Benchmark [Member]
Number of Major Customers	10,000,000
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Ten Customers [Member]
Concentration Risk, Percentage		44.00%	43.00%	53.00%
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | One Customer [Member]
Number of Major Customers		1	0
Forecast [Member]
Insurance Policy Primary Occurence Limit					$ 7,000
Insurance Policy Excess Coverage					3,000
Insurance Policy Excess Coverage					$ 3,000
Transport Enterprise Leasing LLC [Member]
Equity Method Investment, Ownership Percentage	49.00%	49.00%	49.00%