v3.26.1
INVESTMENT SECURITIES - Summary of Amortized Cost and Approximate Fair Value of Investment Securities (Detail) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2025
Jun. 30, 2026
Mar. 31, 2026
Dec. 31, 2025
Mar. 31, 2025
Dec. 31, 2024
Debt Securities, Available-for-sale [Line Items]              
Amortized Cost     $ 2,666,709   $ 1,982,147    
Allowance for Credit Losses $ (17,356) $ (17,356) (29,910) $ (24,566) (28,805) $ (13,127) $ (7,604)
Gross Unrealized Gains     5,708   9,184    
Gross Unrealized Losses     (46,541)   (55,991)    
Fair Value     2,595,966   1,906,535    
Equity securities     30,751   31,111    
Total investment securities, at fair value     2,626,717   1,937,646    
Available-for-sale debt securities, accrued interest     10,200   9,200    
Impairment loss on securities without a readily determinable fair value 2,300 2,300          
Asset-backed securities              
Debt Securities, Available-for-sale [Line Items]              
Amortized Cost     300,305   239,259    
Allowance for Credit Losses (584) (584) 0 (42) (586) (353) (362)
Gross Unrealized Gains     1,187   0    
Gross Unrealized Losses     0   (860)    
Fair Value     301,492   237,813    
Agency-guaranteed residential mortgage-backed securities              
Debt Securities, Available-for-sale [Line Items]              
Amortized Cost     754,024   410,648    
Allowance for Credit Losses     0   0    
Gross Unrealized Gains     2,372   3,238    
Gross Unrealized Losses     (5,401)   (125)    
Fair Value     750,995   413,761    
Agency-guaranteed residential collateralized mortgage obligations              
Debt Securities, Available-for-sale [Line Items]              
Amortized Cost     852,422   496,595    
Allowance for Credit Losses     0   0    
Gross Unrealized Gains     1,582   4,307    
Gross Unrealized Losses     (9,138)   (7,395)    
Fair Value     844,866   493,507    
Agency-guaranteed commercial collateralized mortgage obligations              
Debt Securities, Available-for-sale [Line Items]              
Amortized Cost     116,879   118,049    
Allowance for Credit Losses     0   0    
Gross Unrealized Gains     150   548    
Gross Unrealized Losses     (5,004)   (3,021)    
Fair Value     112,025   115,576    
Corporate notes              
Debt Securities, Available-for-sale [Line Items]              
Amortized Cost     280,206   340,793    
Allowance for Credit Losses $ (16,772) $ (16,772) (29,910) $ (24,524) (28,219) $ (12,774) $ (7,135)
Gross Unrealized Gains     417   1,091    
Gross Unrealized Losses     (13,834)   (27,807)    
Fair Value     236,879   285,858    
Private label collateralized mortgage obligations              
Debt Securities, Available-for-sale [Line Items]              
Amortized Cost     362,873   376,803    
Allowance for Credit Losses     0   0    
Gross Unrealized Gains     0   0    
Gross Unrealized Losses     (13,164)   (16,783)    
Fair Value     $ 349,709   $ 360,020