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Note 5 - Property, Plant and Equipment (Details Textual) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		9 Months Ended
	Apr. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Jul. 12, 2018
Property Subject to or Available for Operating Lease, Gross			$ 285,300		$ 285,300
Property Subject to or Available for Operating Lease, Accumulated Depreciation			178,600		178,600
Depreciation, Total			5,500	$ 6,500	16,900	$ 20,200
Asset Impairment Charges, Total			83	15	2,316	631
Proceeds from Sale of Property, Plant, and Equipment, Total					7,089	4,707
Gain (Loss) on Disposition of Property Plant Equipment, Total			(40)	$ (63)	1,765	$ 300
Goodwill, Ending Balance			$ 6,728		6,728		$ 6,728
Asphalt Terminalling Facility in Oklahoma [Member]
Business Combination, Consideration Transferred, Total		$ 22,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment, Total		11,500
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill, Total		7,600
Goodwill, Ending Balance		$ 2,900
Divestiture [Member] \| Disposal Group, Not Discontinued Operations [Member]
Disposal Group, Including Discontinued Operation, Consideration								$ 90,000
Producer Field Services Business [Member] \| Disposal Group, Not Discontinued Operations [Member]
Proceeds from Divestiture of Businesses	$ 3,000
Gain (Loss) on Disposition of Business	$ 400
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 [Member]
Proceeds from Sale of Property, Plant, and Equipment, Total					1,600
Gain (Loss) on Disposition of Property Plant Equipment, Total					300
Pipeline Linefill Sold in December 2018 [Member]
Proceeds from Sale of Property, Plant, and Equipment, Total					2,600
Cimarron Express Pipeline, LLC [Member]
Asset Impairment Charges, Total					$ 2,000