Note 10 - Intangible Assets and Goodwill (Tables)

12 Months Ended

Dec. 31, 2021

Notes Tables

Schedule of Finite-Lived Intangible Assets [Table Text Block]

	December 31, 2021					December 31, 2020
	Gross Carrying Amount		Accumulated Amortization			Gross Carrying Amount		Accumulated Amortization
	(Dollars in thousands)					(Dollars in thousands)
Amortized intangible assets
Electricity segment	$	417,479	$	(96,250	)	$	227,811	$	(80,622	)
Storage segment		55,973		(13,888	)		55,973		(8,741	)
Total	$	473,452	$	(110,138	)	$	283,784	$	(89,363	)

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]

	(Dollars in thousands)
Year ending December 31:
2022	$	27,429
2023		27,359
2024		26,398
2025		26,079
2026		25,368
Thereafter		230,681
Total	$	363,314

Schedule of Goodwill [Table Text Block]

	2021			2020
	(Dollars in thousands)
Goodwill as of January 1,	$	24,566		$	20,140
Goodwill acquired (1)		65,441			4,107
Translation differences		(53	)		319
Goodwill as of December 31,	$	89,954		$	24,566