v3.25.2
Cover Page - shares
 6 Months Ended
Jun. 30, 2025
Jul. 31, 2025
Entity Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Jun. 30, 2025  
Document Transition Report false  
Entity File Number 001-35077  
Entity Registrant Name WINTRUST FINANCIAL CORP  
Entity Incorporation, State or Country Code IL  
Entity Tax Identification Number 36-3873352  
Entity Address, Address Line One 9700 W. Higgins Road, Suite 800  
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  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Large Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding (in shares)   66,952,288
Entity Central Index Key 0001015328  
Current Fiscal Year End Date --12-31  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q2  
Amendment Flag 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  
7.875% Fixed-Rate Reset Non-Cumulative Perpetual Preferred Stock, Series F, no par value    
Entity Information [Line Items]    
Title of 12(b) Security 7.875% Fixed-Rate Reset Non-Cumulative Perpetual Preferred Stock, Series F, no par value  
Trading Symbol WTFCN  
Security Exchange Name NASDAQ