| Document and Entity Information | Feb. 10, 2021 |
| Cover [Abstract] | |
| Entity Registrant Name | SILGAN HOLDINGS INC |
| Amendment Flag | false |
| Entity Central Index Key | 0000849869 |
| Document Type | 8-K |
| Document Period End Date | Feb. 10, 2021 |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 000-22117 |
| Entity Tax Identification Number | 06-1269834 |
| Entity Address, Address Line One | 4 Landmark Square |
| Entity Address, City or Town | Stamford |
| Entity Address, State or Province | CT |
| Entity Address, Postal Zip Code | 06901 |
| City Area Code | (203) |
| Local Phone Number | 975-7110 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, par value $0.01 per share |
| Trading Symbol | SLGN |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
