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Note 1 - Nature of Activities and Summary of Significant Accounting Policies (Details Textual) $ in Thousands, gal in Millions	1 Months Ended		3 Months Ended		6 Months Ended	9 Months Ended	12 Months Ended
	May 31, 2022 USD ($)	Oct. 31, 2020 USD ($)	Mar. 31, 2023 USD ($) gal	Dec. 31, 2022 USD ($)	Jun. 30, 2023 USD ($)	Sep. 30, 2023 USD ($) MMBTU	Dec. 31, 2022 USD ($)
Renewable Natural Gas in Storage (Millions of British Thermal Unit) | MMBTU						64,690
Other Receivable [Member]
Accumulated Deferred Investment Tax Credit						$ 55,200
U.S. Department of Food And Agriculture Forest Service [Member]
Awarded Grants					$ 245
Proceeds from Grantors					245
LCFPP [Member]
Awarded Grants						4,200
Proceeds from Grantors						3,800
CDFAs[Member]
Awarded Grants		$ 7,800
Proceeds from Grantors						$ 4,800
CEC [Member]
Awarded Grants					8,000
Proceeds from Grantors					4,200
Unearned Grant Proceeds					1,700		$ 1,700
Matching Contribution					1,600
CEC [Member] | Maximum [Member]
Awarded Grants					5,000
CAL FIRE Business and Workforce Development Grant Program [Member]
Awarded Grants	$ 2,000
Proceeds from Grantors							0
Matching Contribution	5,800
CAL Fire [Member]
Awarded Grants	500
Proceeds from Grantors							$ 0
US Forest Service [Member]
Awarded Grants	642
Matching Contribution	$ 2,400
AAFK Plan [Member]
Awarded Grants					6,000
Matching Contribution					5,300
PG&E SEM Incentive Program [Member]
Proceeds from Grantors				$ 374	$ 27
CEC PG&E Pipeline Interconnect [Member]
Proceeds from Grantors			$ 5,000
Kakinada Plant [Member]
GallonPerYear (Gallon) | gal			50

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- Definition

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+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 27
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482525/740-10-45-27

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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-Publisher FASB
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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
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-Publisher FASB
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