Investments in Affiliates - Summary of Transactions in, and Earnings from, Investments in Affiliates (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Investments In And Advances To Affiliates [Line Items]
Change in Unrealized Appreciation (Depreciation)	$ 105	$ (8,050)	$ (19,624)	$ (3,528)
Dividend Income	354,744	536,647	808,682	1,012,389
Affiliated Investments [Member] | Invesco Government & Agency Portfolio, Institutional Class [Member]
Investments In And Advances To Affiliates [Line Items]
Beginning Value	32,298,518	38,232,956	35,846,173	68,087,284
Purchases at Cost	6,562,211	22,075,423	11,283,353	66,446,806
Proceeds from Sales	(15,656,999)	(27,981,827)	(23,925,796)	(102,207,538)
Ending Value	23,203,730	32,326,552	23,203,730	32,326,552
Dividend Income	$ 354,744	$ 536,647	$ 808,682	$ 1,012,389