Note 6 - Claims Liabilities (Details Textual) - USD ($)	Dec. 31, 2019	Sep. 01, 2019	Dec. 31, 2018
Self Insurance Auto Liability Claims Threshold Amount		$ 1,000,000
Workers Compensation Self Insured Retention	$ 500,000
Workers Compensation Per Occurrence Excess Policy	500,000
Letters of Credit Outstanding, Amount	430,000		$ 700,000
Stop Loss for Self Insurance for Employee Health Claims Per Covered Employee Per Year	350,000
Cargo Loss Coverage [Member]
Per Occurrence Deductibles	10,000
Auto Liability Coverage [Member]
Per Occurrence Deductibles	2,500
Self Insurance Auto Liability Claims Threshold Amount	1,000,000	$ 1,000,000
Workers Compensation Coverage [Member]
Letters of Credit Outstanding, Amount	430,000
Certificates of Deposit, at Carrying Value	$ 300,000