Related Party Transactions - Narratives (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Related Party Transaction
Property Management Fee, Percent Fee	1.00%
Document Period End Date	Mar. 31, 2020
Distribution Paid
Loans Disposition Fee Due to Manager			$ 1.0
Terra Fund 5, Terra JV and TIF3
Distribution Paid
Investment Company, Tax Return of Capital Distribution	$ 8.8
Proceeds from Equity Method Investment, Distribution, Return of Capital	$ 8.3
Terra Fund 5
Distribution Paid
Investment Company, Tax Return of Capital Distribution		$ 7.6
Proceeds from Equity Method Investment, Distribution, Return of Capital		$ 3.6
Limited Partner
Related Party Transaction
Percent of Origination Fees Payable	0.01
Loans Disposition Fee Due to Manager Percent	1.00%
Disposition and Extension Fee Payment Term	The disposition fee is paid concurrently with the closing of any such disposition of all or any portion of any real estate-related loan or any interest therein, which is the lesser of (i) 1% of the principal amount of the loan or debt-related loan prior to such transaction or (ii) the amount of the fee paid by the borrower in connection with such transaction. If the Company takes ownership of a property as a result of a workout or foreclosure of a loan, the Company will pay a disposition fee upon the sale of such property equal to 1% of the sales price.