Annual report [Section 13 and 15(d), not S-K Item 405]

GOODWILL AND INTANGIBLE ASSETS (Schedule of Information Concerning Intangible Assets with Finite Life) (Details)

v3.25.4
GOODWILL AND INTANGIBLE ASSETS (Schedule of Information Concerning Intangible Assets with Finite Life) (Details) - USD ($)
Dec. 31, 2025
Apr. 01, 2025
Dec. 31, 2024
Apr. 01, 2024
Finite-Lived Intangible Assets [Line Items]        
Goodwill, Gross Carrying Value $ 1,214,053,000   $ 925,211,000  
Goodwill 1,733,287,000   1,214,053,000  
Gross Carrying Value     1,214,053,000  
Accumulated Amortization, Goodwill 0   0  
Total estimated amortization expense 315,544,000      
American National        
Finite-Lived Intangible Assets [Line Items]        
Goodwill 288,800,000   288,842,000 $ 288,842,000
Sandy Spring        
Finite-Lived Intangible Assets [Line Items]        
Goodwill 519,234,000 $ 519,234,000    
CDIs        
Finite-Lived Intangible Assets [Line Items]        
Gross Carrying Value 153,740,000   85,491,000  
Accumulated Amortization (131,740,000)   (85,768,000)  
Total estimated amortization expense 265,351,000   74,133,000  
CDIs | American National        
Finite-Lived Intangible Assets [Line Items]        
Gross Carrying Value     74,410,000  
CDIs | Sandy Spring        
Finite-Lived Intangible Assets [Line Items]        
Gross Carrying Value 243,351,000      
Other amortizable intangibles        
Finite-Lived Intangible Assets [Line Items]        
Gross Carrying Value 14,041,000   3,977,000  
Accumulated Amortization (11,147,000)   (3,824,000)  
Total estimated amortization expense 50,193,000   10,430,000  
Other amortizable intangibles | American National        
Finite-Lived Intangible Assets [Line Items]        
Gross Carrying Value     $ 10,277,000  
Other amortizable intangibles | Sandy Spring        
Finite-Lived Intangible Assets [Line Items]        
Gross Carrying Value $ 47,299,000