Note 8 - Debt - Current and Long-term Debt (Details) (Parentheticals)	Dec. 31, 2020	Dec. 31, 2019
Revenue Equipment Installment Notes [Member]
Interest rate	2.00%	3.70%
Real Estate Note [Member]
Interest rate	1.90%	3.30%

Contractual interest rate for funds borrowed, under the debt agreement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant