Loans Held for Investment, net - Loan Portfolio (Details) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2026 USD ($) loan	Dec. 31, 2025 USD ($) loan	Jun. 30, 2026 USD ($)	Sep. 30, 2025 USD ($)	Jun. 30, 2025 USD ($)	Dec. 31, 2024 USD ($)
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Loans \| loan	26	24
Amortized Cost \| $	$ 703,765	$ 685,707	$ 719,634	$ 612,424	$ 631,318	$ 609,916
Percentage of Value	100.00%	100.00%
South
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Loans \| loan	9	8
Amortized Cost \| $	$ 275,739	$ 222,512
Percentage of Value	39.00%	32.00%
East
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Loans \| loan	8	7
Amortized Cost \| $	$ 240,637	$ 223,240
Percentage of Value	34.00%	33.00%
West
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Loans \| loan	8	6
Amortized Cost \| $	$ 163,752	$ 134,741
Percentage of Value	23.00%	20.00%
Midwest
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Loans \| loan	1	3
Amortized Cost \| $	$ 23,637	$ 105,214
Percentage of Value	4.00%	15.00%
Multifamily
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Loans \| loan	4	3
Amortized Cost \| $	$ 134,534	$ 87,920
Percentage of Value	19.00%	13.00%
Industrial
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Loans \| loan	4	4
Amortized Cost \| $	$ 113,361	$ 112,792
Percentage of Value	16.00%	16.00%
Office
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Loans \| loan	4	6
Amortized Cost \| $	$ 95,705	$ 165,745
Percentage of Value	14.00%	24.00%
Hotel
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Loans \| loan	3	4
Amortized Cost \| $	$ 90,207	$ 121,393
Percentage of Value	13.00%	18.00%
Student Housing
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Loans \| loan	3	4
Amortized Cost \| $	$ 79,527	$ 115,575
Percentage of Value	11.00%	17.00%
Retail
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Loans \| loan	3	0
Amortized Cost \| $	$ 68,753	$ 0
Percentage of Value	10.00%	0.00%
Medical Office
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Loans \| loan	2	0
Amortized Cost \| $	$ 47,917	$ 0
Percentage of Value	7.00%	0.00%
Self Storage
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Loans \| loan	2	2
Amortized Cost \| $	$ 39,275	$ 47,990
Percentage of Value	5.00%	7.00%
Mixed Use
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Loans \| loan	1	1
Amortized Cost \| $	$ 34,486	$ 34,292
Percentage of Value	5.00%	5.00%