| Document and Entity Information Document | Jul. 27, 2023 |
| Entity Information [Line Items] | |
| Document Type | 8-K |
| Document Period End Date | Jul. 27, 2023 |
| Entity Registrant Name | WINTRUST FINANCIAL CORP |
| Entity Central Index Key | 0001015328 |
| Amendment Flag | false |
| Current Fiscal Year End Date | --12-31 |
| Entity Incorporation, State or Country Code | IL |
| Entity File Number | 001-35077 |
| Entity Tax Identification Number | 36-3873352 |
| Entity Address, Address Line One | 9700 West Higgins Road |
| Entity Address, City or Town | Rosemont |
| Entity Address, State or Province | IL |
| Entity Address, Postal Zip Code | 60018 |
| City Area Code | 847 |
| Local Phone Number | 939-9000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Common Stock, no par value | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | Common stock, no par value |
| Trading Symbol | WTFC |
| Security Exchange Name | NASDAQ |
| Series D Preferred Stock, no par value | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | Series D Preferred Stock, no par value |
| Trading Symbol | WTFCM |
| Security Exchange Name | NASDAQ |
| Depositary Shares, Series E Preferred Stock [Member] | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | Series E Preferred Stock, no par value |
| Trading Symbol | WTFCP |
| Security Exchange Name | NASDAQ |
