Loans - Secured Loans Characteristics (Details)	12 Months Ended
	Dec. 31, 2021 USD ($) County Loan	Dec. 31, 2020 USD ($) Loan County	Dec. 31, 2019 USD ($)
Secured Loan Transactions [Line Items]
Number of secured loans | Loan	31	33
Secured loans - principal (in Dollars)	$ 55,099,000	$ 74,080,000	$ 86,203,000
Average secured loan - principal (in Dollars)	$ 1,777,000	$ 2,245,000
Average principal as percent of total principal	3.20%	3.00%
Average principal as percent of partners’ capital, net of formation loan	2.70%	2.90%
Average principal as percent of total assets	2.60%	2.70%
Largest secured loan - principal (in Dollars)	$ 7,994,000	$ 10,200,000
Largest principal as percent of total principal	14.50%	13.80%
Largest principal as percent of partners’ capital, net of formation loan	12.20%	13.00%
Largest principal as percent of total assets	11.70%	12.10%
Smallest secured loan - principal (in Dollars)	$ 56,000	$ 46,000
Smallest principal as percent of total principal	0.10%	0.10%
Smallest principal as percent of partners’ capital, net of formation loan	0.10%	0.10%
Smallest principal as percent of total assets	0.10%	0.10%
Number of California counties where security is located | County	12	14
Largest percentage of principal in one California county	32.10%	40.00%
Minimum [Member]
Secured Loan Transactions [Line Items]
Secured loans - interest rate (fixed)	7.30%	5.00%
Maximum [Member]
Secured Loan Transactions [Line Items]
Secured loans - interest rate (fixed)	10.80%	10.80%