Cover
Cover | 9 Months Ended | |
Aug. 09, 2022 | Jun. 30, 2022 | |
Cover [Abstract] | ||
Document Type | 8-K | |
Document Period End Date | Aug. 09, 2022 | |
Entity Registrant Name | GOLUB CAPITAL BDC, INC. | |
Entity Incorporation, State or Country Code | DE | |
Securities Act File Number | 814-00794 | |
Entity Tax Identification Number | 27-2326940 | |
Entity Address, Address Line One | 200 Park Avenue | |
Entity Address, Address Line Two | 25th Floor | |
Entity Address, City or Town | New York | |
Entity Address, State or Province | NY | |
Entity Address, Postal Zip Code | 10166 | |
City Area Code | 212 | |
Local Phone Number | 750-6060 | |
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 $0.001 per share | |
Trading Symbol | GBDC | |
Security Exchange Name | NASDAQ | |
Entity Emerging Growth Company | false | |
Amendment Flag | false | |
Entity Central Index Key | 0001476765 |