| Document and Entity Information | Oct. 12, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Oct. 12, 2020 |
| Entity Registrant Name | ALLSCRIPTS HEALTHCARE SOLUTIONS, INC. |
| Entity Central Index Key | 0001124804 |
| Entity Emerging Growth Company | false |
| Entity File Number | 001-35547 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 36-4392754 |
| Entity Address, Address Line One | 222 Merchandise Mart Plaza |
| Entity Address, Address Line Two | Suite 2024 |
| Entity Address, City or Town | Chicago |
| Entity Address, State or Province | IL |
| Entity Address, Postal Zip Code | 60654 |
| City Area Code | (800) |
| Local Phone Number | 334-8534 |
| 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 $0.01 per share |
| Trading Symbol | MDRX |
| Security Exchange Name | NASDAQ |
