COMMITMENTS AND CONTINGENCIES - Unfunded commitments (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Unfunded commitments
Total Unfunded Commitments	$ 37,031	$ 53,113
Revolving Loan Commitments
Unfunded commitments
Total Unfunded Commitments	15,801	25,053
Revolving Loan Commitments | ABB/Con-cise Optical Group LLC (d/b/a ABB Optical Group, LLC)
Unfunded commitments
Total Unfunded Commitments	158
Revolving Loan Commitments | Bridgepoint Healthcare, LLC
Unfunded commitments
Total Unfunded Commitments	1,588	1,588
Revolving Loan Commitments | Camp Facility Services Holdings, LLC (d/b/a Camp Construction Services, Inc.)
Unfunded commitments
Total Unfunded Commitments		2,031
Revolving Loan Commitments | Claridge Products and Equipment, LLC
Unfunded commitments
Total Unfunded Commitments	56	491
Revolving Loan Commitments | Coastal Television Broadcasting Group LLC
Unfunded commitments
Total Unfunded Commitments	309	309
Revolving Loan Commitments | EducationDynamics, LLC
Unfunded commitments
Total Unfunded Commitments	960	1,199
Revolving Loan Commitments | Epiphany Business Services, LLC (d/b/a Epiphany Dermatology, PA)
Unfunded commitments
Total Unfunded Commitments		438
Revolving Loan Commitments | I&I Sales Group, LLC (d/b/a Avision Sales Group)
Unfunded commitments
Total Unfunded Commitments		619
Revolving Loan Commitments | HC Salon Holdings, Inc. (d/b/a Hair Cuttery)
Unfunded commitments
Total Unfunded Commitments	700	700
Revolving Loan Commitments | HRG Management, LLC (d/b/a HomeRiver Group, LLC)
Unfunded commitments
Total Unfunded Commitments		1,083
Revolving Loan Commitments | Industrial Specialty Services USA LLC
Unfunded commitments
Total Unfunded Commitments	295	1,182
Revolving Loan Commitments | Inspired Beauty Brands, Inc.
Unfunded commitments
Total Unfunded Commitments	531	531
Revolving Loan Commitments | ITS Buyer Inc. (d/b/a ITS Logistics, LLC)
Unfunded commitments
Total Unfunded Commitments		592
Revolving Loan Commitments | IvyRehab Intermediate II, LLC (d/b/a Ivy Rehab)
Unfunded commitments
Total Unfunded Commitments		403
Revolving Loan Commitments | Juniper Landscaping Holdings LLC
Unfunded commitments
Total Unfunded Commitments		597
Revolving Loan Commitments | LHS Borrower, LLC (d/b/a Leaf Home, LLC)
Unfunded commitments
Total Unfunded Commitments		560
Revolving Loan Commitments | LMG Holdings, Inc.
Unfunded commitments
Total Unfunded Commitments		414
Revolving Loan Commitments | Max Solutions Inc
Unfunded commitments
Total Unfunded Commitments	161
Revolving Loan Commitments | Max Solutions Inc.
Unfunded commitments
Total Unfunded Commitments	1,212
Revolving Loan Commitments | Motivational Marketing, LLC (d/b/a Motivational Fulfillment)
Unfunded commitments
Total Unfunded Commitments	1,182	1,182
Revolving Loan Commitments | MSI Information Services, Inc.
Unfunded commitments
Total Unfunded Commitments	750
Revolving Loan Commitments | Naviga Inc. (f/k/a Newscycle Solutions, Inc.)
Unfunded commitments
Total Unfunded Commitments	34	132
Revolving Loan Commitments | PFB Holdco, Inc. (d/b/a PFB Corporation)
Unfunded commitments
Total Unfunded Commitments	882	963
Revolving Loan Commitments | PFB Holdco, Inc. (d/b/a PFB Corporation)
Unfunded commitments
Total Unfunded Commitments	296	296
Revolving Loan Commitments | PG Dental New Jersey Parent, LLC
Unfunded commitments
Total Unfunded Commitments	352	232
Revolving Loan Commitments | PPS CR Acquisition, Inc. (d/b/a Power Plant Services)
Unfunded commitments
Total Unfunded Commitments	3,030	3,030
Revolving Loan Commitments | RLJ Pro-Vac, Inc. (d/b/a Pro-Vac)
Unfunded commitments
Total Unfunded Commitments		1,013
Revolving Loan Commitments | Sleep OpCo LLC (d/b/a Brooklyn Bedding LLC)
Unfunded commitments
Total Unfunded Commitments	2,646	2,646
Revolving Loan Commitments | Telestream Holdings Corporation
Unfunded commitments
Total Unfunded Commitments	397	795
Revolving Loan Commitments | The Kyjen Company, LLC (d/b/a Outward Hound)
Unfunded commitments
Total Unfunded Commitments	262	554
Revolving Loan Commitments | Trimlite Buyer LLC (d/b/a Trimlite LLC)
Unfunded commitments
Total Unfunded Commitments		1,473
Delayed Draw Loan Commitments
Unfunded commitments
Total Unfunded Commitments	21,230	28,060
Delayed Draw Loan Commitments | Bridgepoint Healthcare, LLC
Unfunded commitments
Total Unfunded Commitments	794	794
Delayed Draw Loan Commitments | Camp Facility Services Holdings, LLC (d/b/a Camp Construction Services, Inc.)
Unfunded commitments
Total Unfunded Commitments	4,063	4,063
Delayed Draw Loan Commitments | EducationDynamics, LLC
Unfunded commitments
Total Unfunded Commitments	1,709	1,709
Delayed Draw Loan Commitments | Empire Office, Inc.
Unfunded commitments
Total Unfunded Commitments		4,926
Delayed Draw Loan Commitments | I&I Sales Group, LLC (d/b/a Avision Sales Group)
Unfunded commitments
Total Unfunded Commitments		2,699
Delayed Draw Loan Commitments | HRG Management, LLC (d/b/a HomeRiver Group, LLC)
Unfunded commitments
Total Unfunded Commitments		1,514
Delayed Draw Loan Commitments | Grupo HIMA San Pablo, Inc.
Unfunded commitments
Total Unfunded Commitments		667
Delayed Draw Loan Commitments | IvyRehab Intermediate II, LLC (d/b/a Ivy Rehab)
Unfunded commitments
Total Unfunded Commitments		1,188
Delayed Draw Loan Commitments | Juniper Landscaping Holdings LLC
Unfunded commitments
Total Unfunded Commitments		2,387
Delayed Draw Loan Commitments | JZ Capital Partners Ltd.
Unfunded commitments
Total Unfunded Commitments	5,714
Delayed Draw Loan Commitments | Max Solutions Inc
Unfunded commitments
Total Unfunded Commitments	2,755
Delayed Draw Loan Commitments | PlayMonster LLC
Unfunded commitments
Total Unfunded Commitments		2,867
Delayed Draw Loan Commitments | Power Service Group CR Acquisition Inc
Unfunded commitments
Total Unfunded Commitments	2,090
Delayed Draw Loan Commitments | Solar Holdings Bidco Limited
Unfunded commitments
Total Unfunded Commitments	3,700
Delayed Draw Loan Commitments | Source Code Holdings, LLC (d/b/a Source Code Corporation)
Unfunded commitments
Total Unfunded Commitments		2,185
Delayed Draw Loan Commitments | Telestream Holdings Corporation
Unfunded commitments
Total Unfunded Commitments	346
Delayed Draw Loan Commitments | True Blue Car Wash, LLC
Unfunded commitments
Total Unfunded Commitments	$ 59	1,145
Delayed Draw Loan Commitments | BBQ Buyer, LLC (d/b/a BBQ Guys)
Unfunded commitments
Total Unfunded Commitments		854
Delayed Draw Loan Commitments | DCA Investment Holding, LLC (d/b/a Dental Care Alliance, LLC)
Unfunded commitments
Total Unfunded Commitments		$ 1,062