Additional Fund Statistics (Details) - Volumetric Fund - C000032757	12 Months Ended
Dec. 31, 2024 USD ($)
Net Assets	$ 40,770,705
Holdings Count	54
Advisory Fees Paid, Amount	$ 749,385
Investment Company, Portfolio Turnover	46.00%

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
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-Paragraph 1
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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 946
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 27
-Publisher FASB
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