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

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

DEBT - Schedule of Maturities Dates and Fixed Interest Rates (Details)

DEBT - Schedule of Maturities Dates and Fixed Interest Rates (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Sep. 30, 2024	Mar. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Debentures	$ 2,134,000			$ 1,810,000
Unsecured Notes \| 3.95% Fixed Interest Rate
Debt Instrument [Line Items]
Debt instrument, interest rate, stated (as a percent)	3.95%
Debentures	$ 0			39,000
Unsecured Notes \| 3.55% Fixed Interest Rate
Debt Instrument [Line Items]
Debt instrument, interest rate, stated (as a percent)	3.55%
Debentures	$ 0			24,800
Unsecured Notes \| 3.52% Fixed Interest Rate
Debt Instrument [Line Items]
Debt instrument, interest rate, stated (as a percent)	3.52%
Debentures	$ 40,400			40,400
Unsecured Notes \| 3.19% Fixed Interest Rate
Debt Instrument [Line Items]
Debt instrument, interest rate, stated (as a percent)	3.19%
Debentures	$ 34,600			34,600
Unsecured Notes \| 3.41% Fixed Interest Rate
Debt Instrument [Line Items]
Debt instrument, interest rate, stated (as a percent)	3.41%
Debentures	$ 43,000			43,000
Unsecured Notes \| 3.55% Fixed Interest Rate
Debt Instrument [Line Items]
Debt instrument, interest rate, stated (as a percent)	3.55%
Debentures	$ 32,000			32,000
Unsecured Notes \| 2.35% Fixed Interest Rate
Debt Instrument [Line Items]
Debt instrument, interest rate, stated (as a percent)	2.35%
Debentures	$ 15,000			15,000
Unsecured Notes \| 1.13% Fixed Interest Rate
Debt Instrument [Line Items]
Debt instrument, interest rate, stated (as a percent)	1.13%
Debentures	$ 10,000			10,000
Unsecured Notes \| 1.31% Fixed Interest Rate
Debt Instrument [Line Items]
Debt instrument, interest rate, stated (as a percent)	1.31%
Debentures	$ 10,000			10,000
Unsecured Notes \| 1.94% Fixed Interest Rate
Debt Instrument [Line Items]
Debt instrument, interest rate, stated (as a percent)	1.94%
Debentures	$ 25,200			25,200
Unsecured Notes \| 1.58% Fixed Interest Rate
Debt Instrument [Line Items]
Debt instrument, interest rate, stated (as a percent)	1.58%
Debentures	$ 60,000			60,000
Unsecured Notes \| 5.74% Fixed Interest Rate
Debt Instrument [Line Items]
Debt instrument, interest rate, stated (as a percent)	5.74%
Debentures	$ 16,000			16,000
Unsecured Notes \| 5.34% Fixed Interest Rate
Debt Instrument [Line Items]
Debt instrument, interest rate, stated (as a percent)	5.34%
Debentures	$ 63,800			0
Unsecured Notes \| SBIC Debentures
Debt Instrument [Line Items]
Debentures	$ 350,000	$ 350,000	$ 286,200	$ 350,000