| Document and Entity Information Document | Jan. 25, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Jan. 25, 2021 |
| Entity Registrant Name | ENTERPRISE FINANCIAL SERVICES CORP |
| Entity Central Index Key | 0001025835 |
| Amendment Flag | false |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-15373 |
| Entity Tax Identification Number | 43-1706259 |
| Entity Address, Address Line One | 150 N. Meramec Avenue |
| Entity Address, City or Town | St. Louis |
| Entity Address, State or Province | MO |
| Entity Address, Postal Zip Code | 63105 |
| City Area Code | 314 |
| Local Phone Number | 725-5500 |
| 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 | EFSC |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
