Other income (Details) - USD ($)	3 Months Ended		9 Months Ended
Other income (Details) - USD ($)	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Other income
Borrower charges	$ 130,871	$ 23,579	$ 163,364	$ 164,296
Lender fees	51,426	26,955	132,397	205,222
In-house legal fees	36,500	7,478	108,200	58,728
Modification and extension fees	86,722	115,544	155,976	194,416
Interest income on investments	28,148	0	28,148	0
Other income	20,004	1,715	62,117	52,168
Total	$ 353,671	$ 175,271	$ 650,202	$ 674,830