v3.26.1
ACQUISITION AND DIVESTITURE ACTIVITY - Schedule of Assets Acquired and Liabilities Assumed and the Fair Value of Consideration (Details) - USD ($)
$ / shares in Units, $ in Thousands
 3 Months Ended 6 Months Ended
May 01, 2025
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Mar. 31, 2026
Dec. 31, 2025
Mar. 31, 2025
Dec. 31, 2024
Assets                
Goodwill   $ 2,409,886 $ 2,429,756 $ 2,409,886 $ 2,429,756 $ 2,425,700 $ 2,175,251 $ 2,175,251
Liabilities                
Securities sold under agreements to repurchase   297,637 265,301 297,637   $ 261,366    
Fair value of consideration                
Common stock (50,183 shares issued at $20.59 per share)   1,033,262 $ 0 $ 1,033,262        
Common Stock                
Fair value of consideration                
Common stock (50,183 shares issued at $20.59 per share)   $ 50,183            
Bremer                
Assets                
Cash and cash equivalents $ 449,757              
Equity securities 26,070              
Investment securities 2,811,108              
FHLB/Federal Reserve Bank stock 93,924              
Loans held-for-sale 9,883              
Loans, net of allowance for credit losses 11,110,423              
Premises and equipment 99,965              
Goodwill 254,505              
Other intangible assets 440,099              
Company-owned life insurance 181,909              
Other assets 793,404              
Total assets 16,271,047              
Liabilities                
Deposits 12,862,357              
Securities sold under agreements to repurchase 49,131              
Federal Home Loan Bank advances 1,559,227              
Other borrowings 205,194              
Accrued expenses and other liabilities 247,243              
Total liabilities 14,923,152              
Fair value of consideration                
Cash 314,633              
Total consideration 1,347,895              
Bremer | Common Stock                
Fair value of consideration                
Common stock (50,183 shares issued at $20.59 per share) $ 1,033,262              
Issuance of common stock shares for acquisitions of business (in shares) 50,183,000              
Share price (in dollars per share) $ 20.59