v3.25.2
Investment Securities - Summary of Continuous Unrealized Loss Position of Securities (Detail) - USD ($)
$ in Thousands
Jun. 30, 2025
Dec. 31, 2024
Schedule of Investments [Line Items]    
Fair Value, Less Than 12 Months, Available-for-sale $ 197,806 $ 207,644
Gross Unrealized Holding Losses, Less Than 12 Months, Available-for-sale (1,038) (855)
Fair Value, 12 Months or Longer, Available-for-sale 2,094,936 2,124,849
Gross Unrealized Holding Losses, 12 Months or Longer, Available-for-sale (364,063) (447,326)
Fair Value, Available-for-sale 2,292,742 2,332,493
Gross Unrealized Holding Losses, Available-for-sale (365,101) (448,181)
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value 91,228 65,740
Gross Unrealized Holding Loss, Less than 12 Months, Held-to-maturity (3,981) (1,109)
Fair Value, 12 Months or Longer, Held-to-maturity 1,801,089 1,811,354
Gross Unrealized Holding Losses, 12 Months or Longer, Held-to-maturity (388,852) (425,372)
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value 1,892,317 1,877,094
Gross Unrealized Holding Losses, Held-to-maturity (392,833) (426,481)
CMO/REMIC [Member]    
Schedule of Investments [Line Items]    
Fair Value, Less Than 12 Months, Available-for-sale   1
Gross Unrealized Holding Losses, Less Than 12 Months, Available-for-sale  
Fair Value, 12 Months or Longer, Available-for-sale 349,609 351,521
Gross Unrealized Holding Losses, 12 Months or Longer, Available-for-sale (112,812) (120,399)
Fair Value, Available-for-sale 349,609 351,522
Gross Unrealized Holding Losses, Available-for-sale (112,812) (120,399)
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value  
Gross Unrealized Holding Loss, Less than 12 Months, Held-to-maturity  
Fair Value, 12 Months or Longer, Held-to-maturity 610,397 613,937
Gross Unrealized Holding Losses, 12 Months or Longer, Held-to-maturity (160,170) (170,121)
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value 610,397 613,937
Gross Unrealized Holding Losses, Held-to-maturity (160,170) (170,121)
Mortgage-backed Securities [Member]    
Schedule of Investments [Line Items]    
Fair Value, Less Than 12 Months, Available-for-sale 192,892 204,428
Gross Unrealized Holding Losses, Less Than 12 Months, Available-for-sale (1,036) (700)
Fair Value, 12 Months or Longer, Available-for-sale 1,725,631 1,757,066
Gross Unrealized Holding Losses, 12 Months or Longer, Available-for-sale (250,072) (325,677)
Fair Value, Available-for-sale 1,918,523 1,961,494
Gross Unrealized Holding Losses, Available-for-sale (251,108) (326,377)
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value 1,922 2,072
Gross Unrealized Holding Loss, Less than 12 Months, Held-to-maturity (5) (42)
Fair Value, 12 Months or Longer, Held-to-maturity 483,518 502,292
Gross Unrealized Holding Losses, 12 Months or Longer, Held-to-maturity (98,097) (109,978)
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value 485,440 504,364
Gross Unrealized Holding Losses, Held-to-maturity (98,102) (110,020)
Municipal Bonds [Member]    
Schedule of Investments [Line Items]    
Fair Value, Less Than 12 Months, Available-for-sale   3,215
Gross Unrealized Holding Losses, Less Than 12 Months, Available-for-sale   (155)
Fair Value, 12 Months or Longer, Available-for-sale 19,696 16,262
Gross Unrealized Holding Losses, 12 Months or Longer, Available-for-sale (1,179) (1,250)
Fair Value, Available-for-sale 19,696 19,477
Gross Unrealized Holding Losses, Available-for-sale (1,179) (1,405)
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value 89,306 63,668
Gross Unrealized Holding Loss, Less than 12 Months, Held-to-maturity (3,976) (1,067)
Fair Value, 12 Months or Longer, Held-to-maturity 292,372 286,868
Gross Unrealized Holding Losses, 12 Months or Longer, Held-to-maturity (38,922) (38,958)
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value 381,678 350,536
Gross Unrealized Holding Losses, Held-to-maturity (42,898) (40,025)
Government Agency/GSE [Member]    
Schedule of Investments [Line Items]    
Fair Value, Less Than 12 Months, Available-for-sale 4,914  
Gross Unrealized Holding Losses, Less Than 12 Months, Available-for-sale (2)  
Fair Value, Available-for-sale 4,914  
Gross Unrealized Holding Losses, Available-for-sale (2)  
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value  
Gross Unrealized Holding Loss, Less than 12 Months, Held-to-maturity  
Fair Value, 12 Months or Longer, Held-to-maturity 414,802 408,257
Gross Unrealized Holding Losses, 12 Months or Longer, Held-to-maturity (91,663) (106,315)
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value 414,802 408,257
Gross Unrealized Holding Losses, Held-to-maturity $ (91,663) $ (106,315)