Organization - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands					3 Months Ended		6 Months Ended
	Jun. 09, 2021	Oct. 28, 2020	Dec. 31, 2018	Nov. 08, 2018	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024	Dec. 18, 2019	Mar. 29, 2019	Mar. 28, 2019
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Company incorporated date							Aug. 08, 2006
Asset coverage requirement percentage											150.00%	200.00%
Incentive fees					$ 967	$ 1,374	$ 1,887	$ 2,608
Common stock, par value					$ 0.01		$ 0.01		$ 0.01
Common stock, issued					9,970,461		9,970,461		9,960,785
Common stock, authorized					20,000,000		20,000,000		20,000,000
Asset Manager Subsidiaries
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Date of acquisition agreement				Nov. 08, 2018
Date of acquisition closing			Dec. 31, 2018
Cash purchase price				$ 37,900
OHAI Transaction
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Common stock, par value										$ 0.01
Share value in cash										$ 0.42
Common stock, issued										0.3688
Additional consideration funded by adviser										$ 0.15
OHAI Transaction \| Common Stock
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Common stock, par value										$ 0.001
GARS Acquisition
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Date of acquisition agreement		Jun. 24, 2020
Share value in cash		$ 1.19
Common stock, issued		1.917
Additional consideration funded by adviser		$ 0.31
GARS Acquisition \| Common Stock
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Common stock, par value		0.01
GARS Acquisition \| GARS Common Stock
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Common stock, par value		$ 0.001
HCAP Acquisition
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Cash purchase price	$ 18,540
Additional consideration funded by adviser	$ 2,150
Business acquisition, number of shares issued	15,252,453
HCAP Acquisition \| Common Stock
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Common stock, par value	$ 0.01

Portman Ridge Finance Corp 10-Q