Schedule IV - Mortgage Loans on Real Estate Schedule IV - Mortgage Loans on Real Estate (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Federal Income Tax Basis	$ 261,170,000
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate	259,491,000	$ 294,120,000	$ 202,877,000	$ 98,110,000
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Principal Amount of Delinquent Loans	0
Financing Receivable, Unamortized Loan Commitment, Origination Fee, and Premium (Discount)	$ 1,414,000
Construction Loans [Member] | Virginia Beach, VA [Member]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Interest Rate	9.00%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Final Maturity Date	Dec. 31, 2023
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Periodic Payment Terms, Description	Interest Only
Mortgage Loans on Real Estate, Carrying Amount of Mortgages	$ 14,000,000
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate	$ 14,000,000
Construction Loans [Member] | Green Bay, WI [Member]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Interest Rate	8.50%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Final Maturity Date	Dec. 31, 2024
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Periodic Payment Terms, Description	Interest Only
Mortgage Loans on Real Estate, Carrying Amount of Mortgages	$ 6,045,000
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate	$ 8,643,000
Construction Loans [Member] | Phoenix, AZ [Member]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Interest Rate	7.25%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Final Maturity Date	Dec. 31, 2028
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Periodic Payment Terms, Description	Interest Only
Mortgage Loans on Real Estate, Carrying Amount of Mortgages	$ 98,752,000
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate	$ 97,614,000
Construction Loans [Member] | Canton, MI [Member]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Interest Rate	9.00%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Final Maturity Date	Dec. 31, 2023
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Periodic Payment Terms, Description	Interest Only
Mortgage Loans on Real Estate, Carrying Amount of Mortgages	$ 11,312,000
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate	$ 14,548,000
Construction Loans [Member] | Chesapeake, VA
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Interest Rate	9.00%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Final Maturity Date	Dec. 31, 2025
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Periodic Payment Terms, Description	Interest Only
Mortgage Loans on Real Estate, Carrying Amount of Mortgages	$ 14,200,000
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate	$ 1,918,000
Construction Loans [Member] | Sussex, WI
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Interest Rate	8.50%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Final Maturity Date	Dec. 31, 2024
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Periodic Payment Terms, Description	Interest Only
Mortgage Loans on Real Estate, Carrying Amount of Mortgages	$ 22,200
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate	$ 3,837,000
Skilled Nursing Facility [Member] | First Mortgage [Member] | Lexington, VA [Member]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Interest Rate	8.00%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Final Maturity Date	Dec. 31, 2032
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Periodic Payment Terms, Description	$21,000
Mortgage Loans on Real Estate, Carrying Amount of Mortgages	$ 3,089,000
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate	$ 1,608,000
Skilled Nursing Facility [Member] | First Mortgage [Member] | Brookneal, VA [Member]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Interest Rate	8.00%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Final Maturity Date	Dec. 31, 2031
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Periodic Payment Terms, Description	$21,000
Mortgage Loans on Real Estate, Carrying Amount of Mortgages	$ 2,780,000
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate	$ 1,557,000
Skilled Nursing Facility [Member] | First Mortgage [Member] | Laurel Fork, VA [Member]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Interest Rate	8.00%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Final Maturity Date	Dec. 31, 2030
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Periodic Payment Terms, Description	$20,000
Mortgage Loans on Real Estate, Carrying Amount of Mortgages	$ 2,672,000
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate	$ 1,443,000
Assisted Living Facility [Member] | First Mortgage [Member] | Oviedo, FL [Member]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Interest Rate	8.25%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Final Maturity Date	Dec. 31, 2021
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Periodic Payment Terms, Description	Interest Only
Mortgage Loans on Real Estate, Carrying Amount of Mortgages	$ 10,000,000
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate	$ 10,000,000
Assisted Living Facility [Member] | First Mortgage [Member] | Indianapolis, IN [Member]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Interest Rate	7.00%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Final Maturity Date	Dec. 31, 2022
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Periodic Payment Terms, Description	Interest Only
Mortgage Loans on Real Estate, Carrying Amount of Mortgages	$ 6,423,000
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate	$ 6,423,000
Assisted Living Facility [Member] | First Mortgage [Member] | Wabash/Lafayette, IN
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Final Maturity Date	Dec. 31, 2025
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Periodic Payment Terms, Description	Interest Only
Mortgage Loans on Real Estate, Carrying Amount of Mortgages	$ 4,000,000
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate	$ 4,000,000
Entrance-Fee Communities [Member] | First Mortgage [Member] | Columbia, SC [Member]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Interest Rate	7.30%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Final Maturity Date	Dec. 31, 2024
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Periodic Payment Terms, Description	Interest Only
Mortgage Loans on Real Estate, Carrying Amount of Mortgages	$ 32,700,000
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate	$ 32,700,000
Note B [Member] | Construction Loans [Member] | Phoenix, AZ [Member]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Interest Rate	8.50%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Final Maturity Date	Dec. 31, 2023
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Periodic Payment Terms, Description	Interest Only
Mortgage Loans on Real Estate, Carrying Amount of Mortgages	$ 61,200,000
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate	$ 61,200,000