Note 2 - Basis of Presentation and Summary of Significant Accounting Policies - Other Property and Equipment, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Other property and equipment, net	$ 3,539	$ 3,587
Land [Member]
Other property and equipment, net	2,139	2,139
Transportation Equipment [Member]
Other property and equipment, net	648	691
Building [Member]
Other property and equipment, net	534	544
Leasehold Improvements [Member]
Other property and equipment, net	213	206
Field Equipment [Member]
Other property and equipment, net	4	6
Furniture and Fixtures [Member]
Other property and equipment, net	$ 1	$ 1