Organization and Basis of Presentation - Additional Information (Details)					12 Months Ended
	Dec. 05, 2022 USD ($) BusinessDays	Jan. 29, 2020 USD ($) shares	Jan. 16, 2020 USD ($) shares	Sep. 27, 2019 USD ($) shares	Dec. 31, 2023 USD ($) shares	Dec. 31, 2022 USD ($) shares	Dec. 31, 2021 USD ($)	Aug. 05, 2021 USD ($)
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Issuance of common stock, net of issuance costs, shares | shares				10
Issuance of common stock, net of issuance costs				$ 150	$ 150,279,000	$ 113,141,000	$ 576,000
Initally contributed capital	$ 21,400,000
Debt instrument percentage					6.00%
Percentage of capital contribution invested in joint venture common equity	30.00%
Percentage of capital contribution invested in joint venture debt notes	70.00%
Percentage of Secured loan and equipment financing advance offered to purchase	40.00%
Percentage of principal amount of loan or equipment financing advance	100
Percentage of fee for loan and advance	50.00%
Loan or advance fee payable number of days | BusinessDays	2
Remaining percentage of fee for loan or advance	50.00%
Percentage of daily average aggregate value of outstanding loans and equipment financings	75
Common stock, shares issued | shares			8,333,333		46,323,712	34,960,672
Proceeds from issuance of common stock			$ 114,400,000		$ 150,279,000	$ 113,141,000	104,784,000
Common stock, value					46,000	35,000
Net proceeds for the sale of investments					$ 146,200,000
Overallotment Option
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Common stock, shares issued | shares		1,333,333	8,333,333
Proceeds from issuance of common stock		$ 20,000,000	$ 125,000,000
Private Offerings | Legacy Funds
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Common stock, shares issued | shares			9,183,185
Common stock, value			$ 137,700,000
Payment of common stock value in cash			$ 108,700,000
Private Offerings | Equity interests
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Common stock, shares issued | shares			533,332
Common stock, value			$ 8,000,000
Payment of common stock value in cash			$ 2,000,000
Maximum
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Percentage of Secured loan and equipment financing advance offered to purchase	25.00%
Trinity Capital Holdings
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Percentage of equity interests acquired					100.00%
Trinity Investor J V I L L C
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Initally contributed capital					$ 11,000,000
Total Investments at fair value					151,600,000
Unfunded capital commitment					10,400,000	21,400,000
Trinity Investor J V I L L C | Debt
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Total Investments at fair value					7,700,000
Trinity Investor J V I L L C | Equity
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Total Investments at fair value					$ 3,300
Senior Credit Corp 2022 LLC
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Joint venture ownership percentage					12.50%
JV Partner
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Initally contributed capital	$ 150,000,000
Joint venture ownership percentage					87.50%
Corporate Joint Venture
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Origination and administrative agent fees						0	$ 0
Other receivables						$ 0
Corporate Joint Venture | Other Assets
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Other receivables					$ 800,000
Corporate Joint Venture | Fee Income
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Origination and administrative agent fees					$ 2,200,000
8.5% Notes
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Debt instrument percentage	8.50%
7.00% Notes due 2025
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Debt instrument percentage			7.00%
7.00% Notes due 2025 | Private Offerings
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Proceeds from issuance of common stock			$ 125,000,000
Trinity Funding 1, LLC | Credit Suisse Credit Facility
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Credit facility			$ 300,000,000
TrinCap Funding, LLC | KeyBank Credit Facility
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Credit facility								$ 350,000,000