Note 9 - Equity Method Investment (Details Textual) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Proceeds from Sale of Property, Plant, and Equipment, Total	$ 18,429	$ 6,623
Income (Loss) from Equity Method Investments, Total	1,490	1,025
Transport Enterprise Leasing LLC [Member]
Proceeds from Sale of Property, Plant, and Equipment, Total	100	0
Revenue from Related Parties	2,100	100
Deferred Gain on Sale of Property	$ 200	$ 100
Equity Method Investment, Ownership Percentage	49.00%
Due from Related Parties, Total	$ 5,300		$ 8,600
Income (Loss) from Equity Method Investments, Total	1,500
Equity Method Investments	21,800		$ 20,100
Transport Enterprise Leasing LLC [Member] \| Reduction in TEL Investment [Member]
Deferred Gain on Sale of Property	$ 200

Amount of gain on the sale of property that does not qualify for gain recognition as of the balance sheet date.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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The cash inflow from the sale of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale.

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Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

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