| Document and Entity Information Document | Aug. 20, 2020 | Aug. 19, 2020 |
| Cover [Abstract] | ||
| Title of 12(b) Security | Common Stock, par value $0.01 per share | |
| Entity Central Index Key | 0001025835 | |
| Document Type | 8-K | |
| Document Period End Date | Aug. 20, 2020 | |
| Entity Registrant Name | ENTERPRISE FINANCIAL SERVICES CORP | |
| 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 | true | |
| Soliciting Material | false | |
| Pre-commencement Tender Offer | false | |
| Pre-commencement Issuer Tender Offer | false | |
| Entity Emerging Growth Company | false | |
| Amendment Flag | false | |
| Trading Symbol | EFSC | |
| Security Exchange Name | NASDAQ |
