Note 1 - Accounting Policies (Details Textual)		12 Months Ended
	Mar. 08, 2022 $ / shares shares	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Bank Overdrafts		$ 0	$ 7,638,000
Due from Employees, Current		43,000	136,000
Other Receivables, Net, Current, Total		7,092,000	5,127,000
Impairment, Long-Lived Asset, Held-for-Use, Total		0	$ 0
Period for Amortizing Prepaid Tires (Month)			24 months
Advertising Expense		$ 1,154,000	$ 1,102,000	$ 1,269,000
Subsequent Event [Member]
Treasury Stock, Shares, Retired (in shares) | shares	12,268,395
Stockholders' Equity Note, Stock Split, Conversion Ratio	2
Common Stock, Dividends, Per Share, Declared (in dollars per share) | $ / shares	$ 1
Truckload Services [Member] | Sales [Member] | Product Concentration Risk [Member]
Concentration Risk, Percentage		67.00%	76.90%	82.70%
Independent Contractors [Member]
Other Receivables, Net, Current, Total		$ 1,037,000	$ 614,000