v3.25.4
OPERATING SEGMENT INFORMATION (Narrative) (Details)
$ in Millions
1 Months Ended 12 Months Ended
Mar. 31, 2025
USD ($)
branch
Mar. 31, 2025
USD ($)
investment
Dec. 31, 2025
branch
segment
state
Segment Reporting Information [Line Items]      
Number of states in which entity operates | state     11
Number of reportable segments | segment     7
Number of branches     407
FirstBank Coachella Valley Branches      
Segment Reporting Information [Line Items]      
Number of branches acquired 4 4  
Deposits acquired | $ $ 630 $ 630  
Loans acquired | $ $ 420 $ 420  
Utah | Zions Bank      
Segment Reporting Information [Line Items]      
Number of branches     92
Idaho | Zions Bank      
Segment Reporting Information [Line Items]      
Number of branches     25
Wyoming | Zions Bank      
Segment Reporting Information [Line Items]      
Number of branches     1
California | CB&T      
Segment Reporting Information [Line Items]      
Number of branches     77
Texas | Amegy      
Segment Reporting Information [Line Items]      
Number of branches     76
Arizona | NBAZ      
Segment Reporting Information [Line Items]      
Number of branches     56
Nevada | NSB      
Segment Reporting Information [Line Items]      
Number of branches     43
Colorado | Vectra      
Segment Reporting Information [Line Items]      
Number of branches     33
New Mexico | Vectra      
Segment Reporting Information [Line Items]      
Number of branches     1
Washington | TCBW      
Segment Reporting Information [Line Items]      
Number of branches     2
Oregon | TCBW      
Segment Reporting Information [Line Items]      
Number of branches     1