| Document and Entity Information | Oct. 30, 2020 |
| Cover [Abstract] | |
| Entity Registrant Name | DUNKIN' BRANDS GROUP, INC. |
| Amendment Flag | false |
| Entity Central Index Key | 0001357204 |
| Document Type | 8-K |
| Document Period End Date | Oct. 30, 2020 |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-35258 |
| Entity Tax Identification Number | 20-4145825 |
| Entity Address, Address Line One | 130 Royall Street |
| Entity Address, City or Town | Canton |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 02021 |
| City Area Code | (781) |
| Local Phone Number | 737-3000 |
| Security 12b Title | Common Stock, $0.001 par value per share |
| Trading Symbol | DNKN |
| Security Exchange Name | NASDAQ |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
