Note 6 - Variable Interest Entities - Assets and Liabilities for the Company's 2015 Variable Interest Entity (Details) - USD ($) $ in Thousands		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Restricted cash and cash equivalents (primarily related to VIEs)		$ 91,962	$ 130,804
Property, plant and equipment, net		2,998,949	2,493,457
Construction-in-process		814,967	893,198
Total assets	[1],[2]	5,208,279	4,611,579	$ 4,425,678
Accounts payable and accrued expenses		214,518	149,423
Long-term debt		1,989,557
Other long-term liabilities		22,107	3,317
Total liabilities		2,756,693	2,581,014
Assets:
Restricted cash and cash equivalents		91,962	130,804	104,166
Property, plant and equipment, net		2,998,949	2,493,457
Construction-in-process		814,967	893,198
Total assets	[1],[2]	5,208,279	4,611,579	$ 4,425,678
Liabilities:
Accounts payable and accrued expenses		214,518	149,423
Long-term debt		1,989,557
Other long-term liabilities		22,107	3,317
Total liabilities		2,756,693	2,581,014
Variable Interest Entity, Primary Beneficiary [Member]
Construction-in-process		376,602	360,508
Assets:
Construction-in-process		376,602	360,508
Variable Interest Entity, Primary Beneficiary [Member] | Project Debt [Member]
Total assets		2,311,992	2,182,215
Total liabilities		1,019,932	1,079,928
Assets:
Total assets		2,311,992	2,182,215
Liabilities:
Total liabilities		1,019,932	1,079,928
Variable Interest Entity, Primary Beneficiary [Member] | Power Purchase Agreement [Member]
Total assets		1,510,059	1,146,350
Total liabilities		75,904	58,900
Assets:
Total assets		1,510,059	1,146,350
Liabilities:
Total liabilities		75,904	58,900
Variable Interest Entity, Primary Beneficiary [Member] | Project Debt [Member]
Restricted cash and cash equivalents (primarily related to VIEs)		91,586
Other current assets		154,781	128,414
Property, plant and equipment, net		1,646,973	1,516,107
Construction-in-process		112,469	104,956
Other long-term assets		306,183	304,766
Accounts payable and accrued expenses		33,357	42,577
Long-term debt		545,954	637,080
Other long-term liabilities		440,621	400,271
Assets:
Restricted cash and cash equivalents			127,972
Other current assets		154,781	128,414
Property, plant and equipment, net		1,646,973	1,516,107
Construction-in-process		112,469	104,956
Other long-term assets		306,183	304,766
Liabilities:
Accounts payable and accrued expenses		33,357	42,577
Long-term debt		545,954	637,080
Other long-term liabilities		440,621	400,271
Variable Interest Entity, Primary Beneficiary [Member] | Power Purchase Agreement [Member]
Restricted cash and cash equivalents (primarily related to VIEs)		0
Other current assets		46,501	29,377
Property, plant and equipment, net		1,155,947	810,384
Construction-in-process		264,133	255,552
Other long-term assets		43,478	51,037
Accounts payable and accrued expenses		14,619	8,552
Long-term debt		0	0
Other long-term liabilities		61,285	50,348
Assets:
Restricted cash and cash equivalents			0
Other current assets		46,501	29,377
Property, plant and equipment, net		1,155,947	810,384
Construction-in-process		264,133	255,552
Other long-term assets		43,478	51,037
Liabilities:
Accounts payable and accrued expenses		14,619	8,552
Long-term debt		0	0
Other long-term liabilities		$ 61,285	$ 50,348

[1] Electricity segment assets include goodwill in the amount of $85.9 million , $85.7 million and $85.3 million as of December 31, 2023, 2022 and 2021, respectively, $66.2 million of which was added in the third quarter of 2021 as a result of the Terra-Gen Transaction as further described under Note 2 to the consolidated financial statements. Energy Storage segment assets include goodwill in the amount of $4.6 million , $4.6 million and $4.6 million as of December 31, 2023, 2022 and 2021, respectively. No goodwill is included in the Product segment assets as of December 31, 2023, 2022 and 2021.

[2] Including unconsolidated investments