Note 11 - Commitments and Contingencies (Details Textual)	Mar. 31, 2021 USD ($)
Lessee, Operating Lease, Liability, to be Paid, Total	$ 826,000
Capital Addition Purchase Commitments [Member] \| Revenue Equipment [Member]
Purchase Obligation, to be Paid, Remainder of Fiscal Year	$ 89,300,000

Amount of lessee's undiscounted obligation for lease payment for operating lease.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=121609121&loc=SL77918701-209980

Name:	us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant