MSC Income Fund Annual report [Section 13 and 15(d), not S-K Item 405]

Annual report [Section 13 and 15(d), not S-K Item 405]

RELATED PARTY TRANSACTIONS - Narrative (Details)

RELATED PARTY TRANSACTIONS - Narrative (Details)													1 Months Ended	12 Months Ended
RELATED PARTY TRANSACTIONS - Narrative (Details)	Jan. 29, 2025	Dec. 11, 2024	Aug. 01, 2024 USD ($) $ / shares shares	May 17, 2024 USD ($)	May 01, 2024 USD ($) $ / shares shares	Feb. 05, 2024 USD ($)	Jan. 31, 2024 USD ($) $ / shares shares	Nov. 01, 2023 USD ($) $ / shares shares	Aug. 01, 2023 USD ($) $ / shares shares	May 01, 2023 USD ($) $ / shares shares	May 02, 2022 USD ($) $ / shares shares	Oct. 30, 2020 component	Sep. 30, 2023 USD ($) $ / shares shares	Dec. 31, 2024 USD ($) shares	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Related Party Transaction [Line Items]
Management fee expense														$ 20,922,000	$ 19,828,000	$ 19,831,000
Waiver of internal administrative services expenses														9,450,000	8,308,000	4,540,000
Accounts payable and other liabilities														$ 4,723,000	255,000
Dutch Auction
Related Party Transaction [Line Items]
Sale of stock, proceeds				$ 2,000,000.0		$ 2,500,000
MSC Income \| Related Party
Related Party Transaction [Line Items]
Sale of stock, number of shares (in shares) \| shares			125,314		157,629		157,035	237,944	174,271	127,877	47,349			1,027,419
Sale of stock, price per share (in dollars per share) \| $ / shares			$ 15.96		$ 15.86		$ 15.92	$ 15.76	$ 15.78	$ 15.64	$ 15.84
Sale of stock, proceeds			$ 2,000,000		$ 2,500,000		$ 2,500,000	$ 3,750,000	$ 2,750,000	$ 2,000,000	$ 750,000
MSC Income \| Advisory Agreement
Related Party Transaction [Line Items]
Effective period		2 years
MSC Income \| Advisory Agreement \| Related Party
Related Party Transaction [Line Items]
Base fee rate (as a percent)												1.75%		1.50%
Number of components related to incentive fee \| component												2
MSC Income \| Advisory Agreement \| Related Party \| Subsequent Event
Related Party Transaction [Line Items]
Base fee rate (as a percent)	1.25%
Advisory agreement, fair value of portfolio, minimum threshold	0.075
MSC Income \| Advisory Agreement, Incentive Rate, Pre-Incentive Fee Net Investment Income \| Related Party
Related Party Transaction [Line Items]
Incentive fee rate (as a percent)												20.00%
MSC Income \| Advisory Agreement, Incentive Rate, Pre-Incentive Fee Net Investment Income \| Related Party \| Subsequent Event
Related Party Transaction [Line Items]
Incentive fee rate (as a percent)	17.50%
MSC Income \| Advisory Agreement - Incentive Rate, Quarterly Hurdle Rate \| Related Party
Related Party Transaction [Line Items]
Incentive fee rate (as a percent)												1.875%
MSC Income \| Advisory Agreement - Incentive Rate, Quarterly Hurdle Rate \| Related Party \| Subsequent Event
Related Party Transaction [Line Items]
Incentive fee rate (as a percent)	1.50%
Advisory agreement, fair value of portfolio threshold	0.20
Advisory agreement, average total assets threshold, percent	0.0100
MSC Income \| Advisory Agreement - Incentive Rate, Annualized Hurdle Rate \| Related Party
Related Party Transaction [Line Items]
Incentive fee rate (as a percent)												7.50%
MSC Income \| Advisory Agreement - Incentive Rate, Annualized Hurdle Rate \| Related Party \| Subsequent Event
Related Party Transaction [Line Items]
Incentive fee rate (as a percent)	6.00%
MSC Income \| Advisory Agreement, Incentive Rate, Pre-Incentive Fee Net Investment Income Below Catch-Up Threshold \| Related Party
Related Party Transaction [Line Items]
Incentive fee rate (as a percent)												100.00%
MSC Income \| Advisory Agreement, Incentive Rate, Pre-Incentive Fee Net Investment Income Below Catch-Up Threshold \| Related Party \| Subsequent Event
Related Party Transaction [Line Items]
Incentive fee rate (as a percent)	50.00%
MSC Income \| Advisory Agreement - Incentive Rate, Quarterly Catch-Up Threshold \| Related Party
Related Party Transaction [Line Items]
Incentive fee rate (as a percent)												2.34375%
MSC Income \| Advisory Agreement - Incentive Rate, Quarterly Catch-Up Threshold \| Related Party \| Subsequent Event
Related Party Transaction [Line Items]
Incentive fee rate (as a percent)	2.30769%
MSC Income \| Advisory Agreement - Incentive Rate, Annualized Catch-Up Threshold \| Related Party
Related Party Transaction [Line Items]
Incentive fee rate (as a percent)												9.375%
MSC Income \| Advisory Agreement - Incentive Rate, Annualized Catch-Up Threshold \| Related Party \| Subsequent Event
Related Party Transaction [Line Items]
Incentive fee rate (as a percent)	9.23077%
MSC Income \| Advisory Agreement - Incentive Rate, Pre-Incentive Fee Net Investment Income Exceeds Catch-Up Threshold \| Related Party
Related Party Transaction [Line Items]
Incentive fee rate (as a percent)												20.00%
MSC Income \| Advisory Agreement - Incentive Rate, Pre-Incentive Fee Net Investment Income Exceeds Catch-Up Threshold \| Related Party \| Subsequent Event
Related Party Transaction [Line Items]
Incentive fee rate (as a percent)	17.50%
MSC Income \| Advisory Agreement - Base Management Fees \| Related Party
Related Party Transaction [Line Items]
Management fee expense														$ 20,900,000	19,800,000	19,800,000
MSC Income \| Advisory Agreement - Subordinated Incentive Fees \| Related Party
Related Party Transaction [Line Items]
Management fee expense														12,500,000	12,600,000	2,100,000
MSC Income \| Advisory Agreement - Incentive Fees, Capital Gains Fees \| Related Party
Related Party Transaction [Line Items]
Management fee expense														0	0	0
MSC Income \| Advisory Agreement - Internal Administrative Services \| Related Party
Related Party Transaction [Line Items]
Management fee expense														10,100,000	8,900,000	5,100,000
Waiver of internal administrative services expenses														$ 9,500,000	8,300,000	4,500,000
MSC Income \| Investment Management Agreement Incentive Rate, Annualize Hurdle Rate \| Related Party \| Subsequent Event
Related Party Transaction [Line Items]
Incentive fee rate (as a percent)	6.00%
MSC Income - HMS Adviser \| Offering Costs \| Related Party
Related Party Transaction [Line Items]
Percentage of payment of offering costs (as a percent)														1.50%
Accounts payable and other liabilities														$ 600,000
Fee paid indirectly															$ 100,000	$ 300,000
Main Street \| Related Party \| Dutch Auction
Related Party Transaction [Line Items]
Sale of stock, number of shares (in shares) \| shares													57,693
Sale of stock, price per share (in dollars per share) \| $ / shares													$ 13.00
Sale of stock, proceeds													$ 800,000