Loans Held for Investment - Summary of the Company's loan portfolio - subnote (Details)	Mar. 31, 2020 USD ($) Loans	Dec. 31, 2019 USD ($) Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Held for Investment	$ 402,969,513	$ 378,612,768
Repurchase agreement payable, net of deferred financing fees	$ 91,352,312	$ 79,608,437
Number Of Loans | Loans	22	23
Floating rate | LIBOR
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Receivable, Basis Spread on Variable Rate	0.99%	1.76%
Number Of Loans | Loans	12
Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Held for Investment	$ 10,000,000
Minimum | Floating rate | LIBOR
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Receivable, Basis Spread on Variable Rate	2.00%	2.25%
Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Held for Investment	$ 50,000,000
Maximum | Floating rate | LIBOR
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Receivable, Basis Spread on Variable Rate	2.50%	2.50%
Repurchase Agreements | Floating rate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Repurchase agreement payable, net of deferred financing fees	$ 92,500,000	$ 81,100,000
Collateralized Mortgage Obligations | Floating rate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Held for Investment	$ 136,100,000	$ 114,800,000