Fair Value of Financial Instruments - Investments Categorization in Fair Value Hierarchy (Detail) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	$ 231,197,454	$ 144,195,000
Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	0	0
Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	0	0
Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	231,197,454	144,195,000
Total Senior Secured Notes
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	78,042,454	48,167,603
Total Senior Secured Notes | Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	0	0
Total Senior Secured Notes | Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	0	0
Total Senior Secured Notes | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	78,042,454	48,167,603
Equity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	153,155,000	96,027,397
Equity | Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	0	0
Equity | Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	0	0
Equity | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	$ 153,155,000	$ 96,027,397