Investments in Affiliates - Summary of Transactions in, and Earnings from, Investments in Affiliates (Detail) - USD ($)	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Investments In And Advances To Affiliates [Line Items]
Beginning Value	$ 4,970,177
Change in Unrealized Appreciation (Depreciation)	662	$ 26,960
Ending Value	13,666,188
Affiliated Investments [Member] \| Money Market Mutual Fund - Invesco Government & Agency Portfolio, Institutional Class [Member]
Investments In And Advances To Affiliates [Line Items]
Beginning Value	4,970,177
Purchases at Cost	21,468,854
Proceeds from Sales	(12,772,843)
Ending Value	13,666,188
Dividend Income	$ 562
Affiliated Investments [Member] \| Money Market Mutual Fund - Invesco Premier U.S. Government Money Portfolio - Institutional Class [Member]
Investments In And Advances To Affiliates [Line Items]
Beginning Value		6,356,398
Purchases at Cost		7,288,266
Proceeds from Sales		(8,729,825)
Ending Value		4,914,839
Dividend Income		$ 22,426

Value of the investment at close of period. For investment in and advances to affiliates, if operations of any controlled companies are different in character from those of the company, group such affiliates within divisions and by type of activities.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
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Gross additions to the investment in and advance to the affiliate.

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At the close of the period, the dividends or interest included in caption 1 of the statement of operations. In addition, show as the final item the aggregate of dividends and interest included in the statement of operations in respect of investments in affiliates not held at the close of the period. The total of this column would be expected to agree with the correlative amount shown on the related statement of operations.

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