Note 6 - Discontinued Operations - Information by Major Classes of Line Items Disclosed as Discontinued Operations in the Consolidated Statements (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Total income on discontinued operations that is presented in the Statements of Operations	$ 0	$ 31	$ (8)	$ 67
Dillco Fluid Service, Inc [Member]
Property and equipment, net	0		0		$ 321
Other assets	0		0		32
Total major classes of assets of the discontinued operation	0		0		353
Accounts payable and accrued liabilities	0		0		6
Other liabilities	0		0		34
Total liabilities included as part of discontinued operations	0		0		$ 40
Revenue	0	0	0	0
Cost of sales	0	(11)	(1)	(11)
Sales, general, and administrative expenses	0	0	0	0
Depreciation and amortization	0	(7)	(6)	(13)
Other expense items that are not major	0	11	(1)	(1)
Pretax loss of discontinued operations related to major classes of pretax profit	0	(7)	(8)	(25)
Gain on disposal	0	38	0	92
Total income on discontinued operations that is presented in the Statements of Operations	$ 0	$ 31	$ (8)	$ 67