Loans - Secured Loans Past Maturity (Details) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2019 USD ($) MortgageLoan		Dec. 31, 2018 USD ($) MortgageLoan	Jun. 30, 2019 USD ($)
Loans Details Secured Loans In Nonaccrual Status [Line Items]
Number of secured loans | MortgageLoan	47		56
Secured loans, principal	$ 86,190	[1]	$ 97,438	$ 96,132
Accrued interest	$ 700		$ 701
Matured Loans [Member]
Loans Details Secured Loans In Nonaccrual Status [Line Items]
Number of secured loans | MortgageLoan	4
Secured loans, principal	$ 11,276
Accrued interest	$ 424
Principal past maturity as percent of total principal	13.00%
Principal [Member] | Matured Loans [Member]
Loans Details Secured Loans In Nonaccrual Status [Line Items]
Secured loans, principal	$ 10,851
Advances [Member] | Matured Loans [Member]
Loans Details Secured Loans In Nonaccrual Status [Line Items]
Secured loans, principal	$ 1

[1] Borrower payments are deposited into an independent bank trust account established and administered by RMC, pursuant to California regulations, and are disbursed to the partnership after an appropriate holding period to ensure the funds are collected. Borrower payments deposited into the trust account are not included in the consolidated financial statements until disbursed to the partnership. At September 30, 2019, there was $69,325 in borrower payments held in the RMC trust account, all of which was disbursed to the partnership by October 22, 2019.