Investments in Affiliates -Summary of Transactions in, and Earnings from, Investments in Affiliates (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Investments in and Advances to Affiliates [Line Items]
Investment Owned, at Fair Value, Beginning Balance			$ 426,822,433
Dividend Income	$ 1,781,823	$ 2,941,478	4,785,718	$ 5,209,447
Affiliated Investments [Member] | Money Market Mutual Fund - Invesco Government & Agency Portfolio, Institutional Class [Member]
Investments in and Advances to Affiliates [Line Items]
Investment Owned, at Fair Value, Beginning Balance	190,718,083	134,166,072	279,113,690	111,534,057
Purchases at Cost	276,439,893	258,294,906	573,521,267	489,138,943
Proceeds from Sales	(263,783,471)	(149,087,560)	(649,260,452)	(357,299,582)
Investment Owned, at Fair Value, Ending Balance	203,374,505	243,373,418	203,374,505	243,373,418
Dividend Income	$ 1,781,823	$ 2,941,478	$ 4,785,718	$ 5,209,447