Note 1 - Summary of Significant Accounting Policies (Details Textual)	12 Months Ended
Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Number of Operating Segments	6
Loss on Deposits Above FDIC Amount	$ 0
Accounts Receivable, Allowance for Credit Loss, Current	496,000	$ 497,000
Letters of Credit Outstanding, Amount	$ 23,100,000	$ 20,700,000
Number of Reportable Segments	4
Revenue Benchmark [Member] \| Customer Concentration Risk [Member] \| Walmart [Member]
Concentration Risk, Percentage	20.00%	19.00%	21.00%
Revenue Benchmark [Member] \| Geographic Concentration Risk [Member] \| UNITED STATES
Concentration Risk, Percentage	99.00%	99.00%	99.00%
Accounts Receivable [Member] \| Customer Concentration Risk [Member] \| Walmart [Member]
Concentration Risk, Percentage	21.00%	19.00%
Uninsured Risk [Member] \| Auto Liability Claim [Member]
Loss Contingency Range Possible Loss Per Claim	$ 2,000,000
Uninsured Risk [Member] \| Workers Compensation Liability Claim [Member]
Loss Contingency Range Possible Loss Per Claim	750,000
Insurance Claims [Member]
Letters of Credit Outstanding, Amount	23,100,000
Supplies and Maintenance Costs [Member]
Amortization	$ 6,900,000	$ 7,200,000	$ 6,600,000
Tractor [Member]
Replacement Of Equipment Period After Purchase (Year)	3 years 10 months 24 days
Useful life (Year)	5 years	5 years
Property, Plant and Equipment, Salvage Value, Percentage	25.00%
Trailer [Member]
Replacement Of Equipment Period After Purchase (Year)	8 years 4 months 24 days
Useful life (Year)	7 years	7 years
Property, Plant and Equipment, Salvage Value, Percentage	35.00%
Refrigerated Containers [Member]
Useful life (Year)	12 years	12 years
Property, Plant and Equipment, Salvage Value, Percentage	0.00%
Tires In Service [Member]
Useful life (Year)		24 months

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For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

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Stated as a percentage, the estimated or actual value of the asset at the end of its useful life or when it is no longer serviceable (cannot be used for its original purpose) divided by its [historical] capitalized cost.

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