Loans - Secured Loans by Property Type (Parenthetical) (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2018 USD ($) MortgageLoan	Dec. 31, 2017 USD ($) MortgageLoan
Loans (Details) - Secured Loans by Property Type [Line Items]
Number of secured loans | MortgageLoan	93	93
Principal | $	$ 57,865,391	$ 54,768,689
Single Family Property-Owner Occupied [Member]
Loans (Details) - Secured Loans by Property Type [Line Items]
Number of secured loans | MortgageLoan	11	10
Principal | $	$ 6,506,239	$ 6,309,036
Single Family Property-NonOwner Occupied [Member]
Loans (Details) - Secured Loans by Property Type [Line Items]
Number of secured loans | MortgageLoan	54	57
Principal | $	$ 31,423,270	$ 31,306,180