Cover
Cover - USD ($) | 12 Months Ended | ||
Dec. 31, 2022 | Mar. 09, 2023 | Jun. 30, 2022 | |
Cover [Abstract] | |||
Document Type | 10-K | ||
Document Annual Report | true | ||
Document Period End Date | Dec. 31, 2022 | ||
Current Fiscal Year End Date | --12-31 | ||
Document Transition Report | false | ||
Entity File Number | 000-56072 | ||
Entity Registrant Name | New Mountain Guardian III BDC, L.L.C. | ||
Entity Address, Address Line One | 1633 Broadway, 48th Floor | ||
Entity Address, City or Town | New York | ||
Entity Address, State or Province | NY | ||
Entity Address, Postal Zip Code | 10019 | ||
City Area Code | 212 | ||
Local Phone Number | 720-0300 | ||
Entity Incorporation, State or Country Code | DE | ||
Entity Tax Identification Number | 84-1918127 | ||
Title of 12(g) Security | Units of Limited Liability Company Interests | ||
Entity Well-known Seasoned Issuer | No | ||
Entity Voluntary Filers | No | ||
Entity Current Reporting Status | Yes | ||
Entity Filer Category | Non-accelerated Filer | ||
Entity Small Business | false | ||
Entity Emerging Growth Company | true | ||
Entity Ex Transition Period | false | ||
ICFR Auditor Attestation Flag | false | ||
Entity Shell Company | false | ||
Entity Common Stock, Shares Outstanding | 114,906,527 | ||
Entity Public Float | $ 0 | ||
Entity Central Index Key | 0001781870 | ||
Amendment Flag | false | ||
Document Fiscal Year Focus | 2022 | ||
Document Fiscal Period Focus | FY |
Audit Information
Audit Information | 12 Months Ended |
Dec. 31, 2022 | |
Audit Information [Abstract] | |
Auditor Firm ID | 34 |
Auditor Name | Deloitte & Touche LLP |
Auditor Location | New York, NY 10112 |