Note 1 - Significant Accounting Policies - Segment By Operating Fleet Revenue (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Total revenue	$ 196,318	$ 164,326	$ 369,884	$ 323,070
Truckload [Member]
Total revenue	170,711	147,631	325,259	293,256
Truckload [Member] \| Covenant Transport, Inc. [Member]
Total revenue	105,648	89,444	201,361	177,287
Truckload [Member] \| Southern Refrigerated Transport, Inc. [Member]
Total revenue	45,594	41,823	86,297	82,523
Truckload [Member] \| Star Transportation Inc [Member]
Total revenue	19,469	16,364	37,601	33,446
Managed Freight [Member]
Total revenue	$ 25,607	$ 16,695	$ 44,625	$ 29,814

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130539-203045

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130545-203045

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130543-203045

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