Note 6 - Investment in Unconsolidated Companies - Unconsolidated Investments Mainly in Power Plants (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Total investment in unconsolidated companies	$ 105,886	$ 98,217
Sarulla [Member]
Total investment in unconsolidated companies	68,968	67,451
Ijen Geothermal Project Company [Member]
Total investment in unconsolidated companies	$ 36,918	$ 30,766