Note 19 - Business Segments - Revenues as Reported in the Geographic Area (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Revenue	[1]	$ 746,044		$ 719,267		$ 692,812
UNITED STATES
Revenue	[1]	377,956	[2]	328,606	[2]	301,132
INDONESIA
Revenue	[1]	0		4,379		28,968
KENYA
Revenue	[1]	121,661		119,094		110,243
TURKEY
Revenue	[1]	88,938		168,699		125,166
CHILE
Revenue	[1]	25,540		980		8,895
GUATEMALA
Revenue	[1]	28,624		27,975		27,991
NEW ZEALAND
Revenue	[1]	31,222		10,451		33,395
HONDURAS
Revenue	[1]	34,446		34,355		10,151
Other Foreign Countries [Member]
Revenue	[1]	$ 37,657		$ 24,728		$ 46,871

[1] Revenues as reported in the geographic area in which they originate.

[2] Electricity segment revenues in the United States are all accounted under lease accounting, except for $61.3 million and $26.9 million for the years December 31, 2019 and 2018 that are accounted under ASC 606 starting in 2018. Product and Energy Storage and Management Services segment revenues in the United States are accounted under ASC 606, as further described under Note 1 to the consolidated financial statements.