Investments in Affiliates (Tables)

12 Months Ended

Dec. 31, 2021

Investments In And Advances To Affiliates Schedule Of Investments [Abstract]

Summary of Transactions in, and Earnings from, Investments in Affiliates

          The following is a summary of the transactions in, and earnings from, investments in affiliates for the year ended December 31, 2021.

	Value 12/31/2020		Purchases at Cost		Proceeds from Sales			Change in Unrealized Appreciation (Depreciation)		Realized Gain (Loss)		Value 12/31/2021		Dividend Income
Investments in Affiliated Money    Market Funds:
Invesco Government & Agency Portfolio,    Institutional Class	$	13,839,876	$	58,895,360	$	(59,790,265	)	$	—	$	—	$	12,944,971	$	3,545

          The following is a summary of the transactions in, and earnings from, investments in affiliates for the year ended December 31, 2020.

	Value 12/31/2019		Purchases at Cost		Proceeds from Sales			Change in Unrealized Appreciation (Depreciation)		Realized Gain (Loss)		Value 12/31/2020		Dividend Income
Investments in Affiliated Money    Market Funds:
Invesco Government & Agency Portfolio,    Institutional Class	$	—	$	39,478,084	$	(25,638,208	)	$	—	$	—	$	13,839,876	$	486
Invesco Premier U.S. Government Money    Portfolio, Institutional Class		4,434,970		46,383,854		(50,818,824	)		—		—		—		20,599
Total	$	4,434,970	$	85,861,938	$	(76,457,032	)	$	—	$	—	$	13,839,876	$	21,085

          The following is a summary of the transactions in, and earnings from, investments in affiliates for the year ended December 31, 2019.

	Value 12/31/2018		Purchases at Cost		Proceeds from Sales			Change in Unrealized Appreciation (Depreciation)		Realized Gain (Loss)		Value 12/31/2019		Dividend Income
Investments in Affiliated Money    Market Funds:
Invesco Premier U.S. Government Money    Portfolio, Institutional Class	$	3,829,452	$	51,266,244	$	(50,660,726	)	$	—	$	—	$	4,434,970	$	49,044