| Document and Entity Information | Jan. 07, 2020 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001420302 |
| Document Type | 8-K |
| Document Period End Date | Jan. 7, 2020 |
| Entity Registrant Name | LogMeIn, Inc. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-34391 |
| Entity Tax Identification Number | 20-1515952 |
| Entity Address, Address Line One | 320 Summer Street |
| Entity Address, City or Town | Boston |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 02210 |
| City Area Code | 781 |
| Local Phone Number | 638-9050 |
| Written Communications | false |
| Soliciting Material | true |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, $0.01 par value per share |
| Trading Symbol | LOGM |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
