v3.22.2.2
Cover
Oct. 14, 2022
Cover [Abstract]  
Document Type 8-K
Document Period End Date Nov. 22, 2022
Entity Registrant Name Main Street Capital Corporation
Entity Incorporation, State or Country Code MD
Securities Act File Number 001-33723
Entity Tax Identification Number 41-2230745
Entity Address, Address Line One 1300 Post Oak Boulevard
Entity Address, Address Line Two 8th Floor
Entity Address, City or Town Houston
Entity Address, State or Province TX
Entity Address, Postal Zip Code 77056
City Area Code 713
Local Phone Number 350-6000
Written Communications false
Soliciting Material false
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
Title of 12(b) Security Common Stock, par value $0.01 per share
Trading Symbol MAIN
Security Exchange Name NYSE
Entity Emerging Growth Company false
Entity Central Index Key 0001396440
Amendment Flag false