Note 4 - Property, Plant and Equipment (Details Textual) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Asset Impairment Charges, Total	$ 5,122	$ 1,119
Property, Plant and Equipment, Net, Ending Balance	226,398		$ 232,777
Proceeds from Sale of Property, Plant, and Equipment, Total	25	6,304
Gain (Loss) on Disposition of Property Plant Equipment, Total	(185)	1,724
Cimarron Express Pipeline, LLC [Member]
Asset Impairment Charges, Total		800
Pipeline Linefill [Member]
Asset Impairment Charges, Total	4,900
Property, Plant and Equipment, Net, Ending Balance	4,000		$ 8,100
Property, Plant and Equipment, Additions	$ 800
Proceeds from Sale of Property, Plant, and Equipment, Total		1,600
Gain (Loss) on Disposition of Property Plant Equipment, Total		200
Asphalt plants in the Midwest [Member]
Asset Impairment Charges, Total		300
Truck Stations [Member]
Proceeds from Sale of Property, Plant, and Equipment, Total		1,600
Gain (Loss) on Disposition of Property Plant Equipment, Total		1,500
Pipeline Linefill Sold in December 2018 [Member]
Proceeds from Sale of Property, Plant, and Equipment, Total		$ 2,600

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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