v3.26.1
Cover Page - shares
 6 Months Ended
Jun. 30, 2026
Aug. 06, 2026
Document Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Jun. 30, 2026  
Document Transition Report false  
Entity File Number 001-42677  
Entity Registrant Name FIRST BUSEY CORPORATION  
Entity Incorporation, State or Country Code NV  
Entity Tax Identification Number 37-1078406  
Entity Address, Address Line One 11440 Tomahawk Creek Parkway  
Entity Address, City or Town Leawood  
Entity Address, State or Province KS  
Entity Address, Postal Zip Code 66211  
City Area Code (217)  
Local Phone Number 365-4544  
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   82,576,956
Current Fiscal Year End Date --12-31  
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q2  
Entity Central Index Key 0000314489  
Amendment Flag false  
Common Stock, $0.001 par value    
Document Information [Line Items]    
Title of 12(b) Security Common Stock, $0.001 par value  
Trading Symbol BUSE  
Security Exchange Name NASDAQ  
Depositary Shares, each representing a 1/40th interest in a share of 8.25% Fixed-Rate Series B Non-Cumulative Perpetual Preferred Stock, $0.001 par value    
Document Information [Line Items]    
Title of 12(b) Security Depositary Shares, each representing a 1/40th interest in a share of 8.25% Fixed-Rate Series B Non-Cumulative Perpetual Preferred Stock  
Trading Symbol BUSEP  
Security Exchange Name NASDAQ