Transactions with Affiliated Companies - Income Information (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	$ 11,662	$ 12,524
Dividend Income	1,012	1,095
Fee Income		310
Non-controlled affiliate company investments
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	2,495	2,804
Dividend Income	53	49
Fee Income	0	0
Non-controlled affiliate company investments \| American Community Homes, Inc.
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	529	846
Dividend Income	0	0
Fee Income	0	0
Non-controlled affiliate company investments \| Ascent Midco, LLC
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	0	170
Dividend Income	53	49
Fee Income	0	0
Non-controlled affiliate company investments \| Familia Dental Group Holdings, LLC
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	0	0
Dividend Income	0	0
Fee Income	0	0
Non-controlled affiliate company investments \| HFZ Capital Group, LLC and MC Asset Management (Corporate), LLC
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	1,518	1,328
Dividend Income	0	0
Fee Income	0	0
Non-controlled affiliate company investments \| Mnine Holdings, Inc
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	226	201
Dividend Income	0	0
Fee Income	0	0
Non-controlled affiliate company investments \| NECB Collections, LLC
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	0	0
Dividend Income	0	0
Fee Income	0	0
Non-controlled affiliate company investments \| Second Avenue SFR Holdings II LLC
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	104	138
Dividend Income	0	0
Fee Income	0	0
Non-controlled affiliate company investments \| SFR Holdco LLC
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	117	117
Dividend Income	0	0
Fee Income	0	0
Non-controlled affiliate company investments \| TJ Management Hold Co LLC
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	1	4
Dividend Income	0	0
Fee Income	0	0
Controlled affiliate company investments
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	0	0
Dividend Income	900	900
Fee Income	0	0
Controlled affiliate company investments \| MRCC Senior Loan Fund I, LLC
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	0	0
Dividend Income	900	900
Fee Income	0	0
Investment, Identifier [Axis]: American Community Homes, Inc. 1
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	240	359
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: American Community Homes, Inc. 2
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	118	233
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: American Community Homes, Inc. 3
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	15	22
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: American Community Homes, Inc. 4
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	54	80
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: American Community Homes, Inc. 5
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	99	148
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: American Community Homes, Inc. 6
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	1	1
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: American Community Homes, Inc. 7
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	2	3
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: American Community Homes, Inc., Common stock
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	0	0
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: American Community Homes, Inc., Revolver
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	0	0
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: Ascent Midco, LLC
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	0	169
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: Ascent Midco, LLC, Class A units
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	0	0
Dividend Income	53	49
Fee Income	0	0
Investment, Identifier [Axis]: Ascent Midco, LLC, Revolver
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	0	1
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: Familia Dental Group Holdings, LLC, Class A units
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	0	0
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: HFZ Capital Group, LLC 1
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	588	564
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: HFZ Capital Group, LLC 2
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	212	203
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: MC Asset Management (Corporate), LLC
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	553	435
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: MC Asset Management (Corporate), LLC, Delayed Draw
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	165	126
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: MC Asset Management (Corporate), LLC, LLC interest
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	0	0
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: MRCC Senior Loan Fund I, LLC
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	0	0
Dividend Income	900	900
Fee Income	0	0
Investment, Identifier [Axis]: Mnine Holdings, Inc. 1
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	0	190
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: Mnine Holdings, Inc. 2
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	2	11
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: Mnine Holdings, Inc., Class B units
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	216	0
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: Mnine Holdings, Inc., Revolver
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	8	0
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: NECB Collections, LLC, LLC units
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	0	0
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: NECB Collections, LLC, Revolver
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	0	0
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: SFR Holdco, LLC, Junior secured loan
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	117	117
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: SFR Holdco, LLC, LLC interest
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	0	0
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: Second Avenue SFR Holdings II LLC, Revolver
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	104	138
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: TJ Management HoldCo, LLC, Common stock
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	0	0
Dividend Income	0	0
Fee Income	0	0
Investment, Identifier [Axis]: TJ Management HoldCo, LLC, Revolver
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income	1	4
Dividend Income	0	0
Fee Income	$ 0	$ 0