Fair Value Measurements - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Fair Value Option Quantitative Disclosures [Line Items]
Transfers into or out of Level 3 in the fair value measurement hierarchy	$ 0	$ 0
Unfunded Commitments	5,865,000	$ 6,056,000
EGCP III [Member]
Fair Value Option Quantitative Disclosures [Line Items]
Unfunded Commitments	$ 5,370,000
End of the investment period	Oct. 12, 2016
Remaining obligation date	Oct. 12, 2023