CMBS Structured Pass Through Certificates, MSCR Notes and Mortgage Backed Securities - Summary of CMBS I/O Strips (Details) - USD ($) $ in Thousands							3 Months Ended	12 Months Ended
	Mar. 18, 2022	Feb. 03, 2022	Sep. 29, 2021	Jun. 11, 2021	May 04, 2021	Apr. 28, 2021	Mar. 31, 2023	Dec. 31, 2022
MSCR Notes
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 10,015	$ 10,313
Collateralized Mortgage-Backed Securities
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 37,007	$ 32,328
Interest Rate							8.67%	7.28%
Current Yield							8.82%	7.45%
Multifamily | CMBS I/O Strip, One
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 1,781	$ 1,807
Interest Rate							2.02%	2.02%
Current Yield							14.58%	14.56%
Multifamily | CMBS I/O Strip, Two
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 16,976	$ 18,364
Interest Rate							2.98%	2.98%
Current Yield							16.44%	15.98%
Multifamily | CMBS I/O Strip, Three
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 5,582	$ 5,676
Interest Rate							1.59%	1.59%
Payments for purchase of securities					$ 15,000	$ 50,000
Current Yield							16.02%	15.52%
Multifamily | CMBS I/O Strip, Four
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 3,636	$ 3,693
Interest Rate							3.39%	3.39%
Current Yield							16.20%	15.73%
Multifamily | CMBS I/O Strip, Five
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 442	$ 455
Interest Rate							2.31%	2.31%
Current Yield							19.65%	18.91%
Multifamily | CMBS I/O Strip, Six
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 3,409	$ 4,188
Interest Rate							1.19%	1.19%
Payments for purchase of securities	$ 50,000	$ 40,000	$ 35,000	$ 80,000
Current Yield							13.75%	13.34%
Multifamily | CMBS IO Strip Seven
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 1,043	$ 1,117
Interest Rate							1.18%	1.18%
Current Yield							17.17%	16.77%
Multifamily | CMBS IO Strip Eight
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 2,405	$ 2,445
Interest Rate							1.89%	1.89%
Current Yield							16.35%	15.87%
Multifamily | CMBS I/O Strip, Nine
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 1,322	$ 1,333
Interest Rate							3.10%	3.10%
Current Yield							14.08%	13.74%
Multifamily | CMBS I/O Strip, Ten
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 247	$ 250
Interest Rate							2.61%	2.61%
Current Yield							14.83%	14.44%
Multifamily | CMBS I/O Strip, Eleven
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 3,673	$ 3,726
Interest Rate							1.92%	1.92%
Current Yield							15.48%	15.03%
Multifamily | CMBS I/O Strip, Twelve
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 3,792	$ 3,822
Interest Rate							2.95%	2.95%
Current Yield							14.04%	13.70%
Multifamily | CMBS I/O Strips
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 44,308	$ 46,876
Interest Rate							2.47%	2.46%
Current Yield							15.77%	15.32%
Multifamily | MSCR Notes One
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 3,899	$ 4,019
Interest Rate							13.98%	13.02%
Current Yield							13.98%	13.02%
Multifamily | MSCR Notes Two
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 4,825	$ 4,988
Interest Rate							10.98%	10.02%
Current Yield							10.98%	10.02%
Multifamily | MSCR Notes Three
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 1,291	$ 1,306
Interest Rate							11.33%	10.37%
Current Yield							12.45%	11.40%
Multifamily | MSCR Notes
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 10,015	$ 10,313
Interest Rate							12.19%	11.23%
Current Yield							12.34%	11.36%
Multifamily | Mortgage Backed Securities 5
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 3,965	$ 4,473
Interest Rate							10.56%	9.29%
Current Yield							10.54%	9.27%
Multifamily | Mortgage Backed Securities 7
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 5,733
Interest Rate							13.07%
Current Yield							13.10%
Single-Family | Mortgage Backed Securities 1
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 9,793	$ 9,638
Interest Rate							7.79%	7.08%
Current Yield							8.11%	7.39%
Single-Family | Mortgage Backed Securities 2
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 8,286	$ 8,966
Interest Rate							4.87%	4.87%
Current Yield							5.07%	5.08%
Single-Family | Mortgage Backed Securities 3
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 535	$ 526
Interest Rate							6.23%	6.23%
Current Yield							6.33%	6.33%
Single-Family | Mortgage Backed Securities 4
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 869	$ 819
Interest Rate							3.60%	3.60%
Current Yield							4.20%	4.23%
Self Storage | Mortgage Backed Securities 6
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value							$ 7,826	$ 7,906
Interest Rate							10.34%	9.57%
Current Yield							10.36%	9.59%