Note 1 - Business and Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2023

Notes Tables

Schedule of Cash and Cash Equivalents [Table Text Block]

	December 31,
	2023		2022		2021
	(Dollars in thousands)
Cash and cash equivalents	$	195,808	$	95,872	$	239,278
Restricted cash and cash equivalents		91,962		130,804		104,166
Total cash and cash equivalents and restricted cash and cash equivalents	$	287,770	$	226,676	$	343,444

Schedule Of Estimated Useful Lives [Table Text Block]

	Years
Buildings	25
Leasehold improvements	15	30
Machinery and equipment — manufacturing and drilling	10
Machinery and equipment — computers	3	5
Energy storage equipment	15
Solar facility equipment	30
Office equipment — furniture and fixtures	5	15
Office equipment — other	5	10
Vehicles	5	7

Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block]

	December 31,			December 31,
	2023			2022
	(Dollars in thousands)
Contract assets (*)	$	18,367		$	16,405
Contract liabilities (*)	$	(18,669	)	$	(8,785	)

	Years Ended December 31,
	2023						2022
	Contract assets			Contract liabilities			Contract assets			Contract liabilities
	(Dollars in thousands)
Recognition of contract liabilities as revenue as a result of performance obligations satisfied	$	—		$	6,883		$	—		$	—
Cash received in advance for which revenues have not yet recognized, net of expenditures made		—			(16,766	)		—			(2,604	)
Reduction of contract assets as a result of rights to consideration becoming unconditional		(4,094	)		—			(23,000	)		—
Contract assets recognized, net of recognized receivables		6,056			—			32,780			—
Net change in contract assets and contract liabilities	$	1,962		$	(9,883	)	$	9,780		$	(2,604	)

Accounting Standards Update and Change in Accounting Principle [Table Text Block]

	Year Ended December 31,
	2023		2022		2021
	(Dollars in thousands)
Electricity revenues accounted under lease accounting	$	542,065	$	529,264	$	502,355
Electricity, Product and Energy Storage revenues accounted under ASC 606		287,359		204,895		160,729
Total consolidated revenues	$	829,424	$	734,159	$	663,084

Accounts Receivable, Allowance for Credit Loss [Table Text Block]

	Years Ended December 31,
	2023		2022
	(Dollars in thousands)
Beginning balance of the allowance for expected credit losses	$	90	$	90
Change in the provision for expected credit losses for the period		—		—
Ending balance of the allowance for expected credit losses	$	90	$	90

Schedule of Weighted Average Number of Shares [Table Text Block]

	Year Ended December 31,
	2023		2022		2021
	(In thousands)
Weighted average number of shares used in computation of basic earnings per share		59,424		56,063		56,004
Add:
Additional shares from the assumed exercise of employee stock-based awards		338		440		398
Weighted average number of shares used in computation of diluted earnings per share		59,762		56,503		56,402

Redeemable Noncontrolling Interest [Table Text Block]

	2023			2022
	(Dollars in thousands)
Redeemable noncontrolling interest as of January 1,	$	9,590		$	9,329
Redeemable noncontrolling interest in results of operation of a consolidated subsidiary		939			638
Cash paid to noncontrolling interest		(246	)		—
Currency translation adjustments		316			(377	)
Redeemable noncontrolling interest as of December 31,	$	10,599		$	9,590