Investments in Affiliates -Summary of Transactions in, and Earnings from, Investments in Affiliates (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Investments in and Advances to Affiliates [Line Items]
Beginning Value	$ 983,150,588
Change in Unrealized Appreciation (Depreciation)	67,543	$ (51,835)
Ending Value	559,836,326
Affiliated Investments [Member]
Investments in and Advances to Affiliates [Line Items]
Beginning Value	983,150,588	626,458,758
Purchases at Cost	333,149,680	408,824,743
Proceeds from Sales	(756,596,676)	(255,236,806)
Change in Unrealized Appreciation (Depreciation)	132,734	(35,400)
Ending Value	559,836,326	780,011,295
Dividend Income	8,329,172	112,013
Affiliated Investments [Member] | Exchange-Traded Fund [Member]
Investments in and Advances to Affiliates [Line Items]
Beginning Value	73,590,524	49,855,000
Change in Unrealized Appreciation (Depreciation)	132,734	(35,400)
Ending Value	73,723,258	49,819,600
Dividend Income	707,766	3,002
Affiliated Investments [Member] | Money Market Mutual Fund - Invesco Government & Agency Portfolio, Institutional Class [Member]
Investments in and Advances to Affiliates [Line Items]
Beginning Value	909,560,064	576,603,758
Purchases at Cost	333,149,680	408,824,743
Proceeds from Sales	(756,596,676)	(255,236,806)
Ending Value	486,113,068	730,191,695
Dividend Income	$ 7,621,406	$ 109,011