Quarterly report pursuant to Section 13 or 15(d)

Securities - Summary of Debt Securities Available for Sale in an Unrealized Loss Position for Which an Allowance for Credit Losses Has Not Been Recorded (Detail)

v3.22.2.2
Securities - Summary of Debt Securities Available for Sale in an Unrealized Loss Position for Which an Allowance for Credit Losses Has Not Been Recorded (Detail)
$ in Thousands
Sep. 30, 2022
USD ($)
Security
Dec. 31, 2021
USD ($)
Security
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ (22,018) $ (9,953)
Available-for-Sale Within One Year, Estimated Fair Value $ 208,146 $ 800,439
Available-for-Sale Within One Year, Number of Securities | Security 67 158
Available-for-Sale More than One Year, Gross Unrealized Loss $ (115,214) $ (2,088)
Available-for-Sale More than One Year, Estimated Fair Value $ 622,005 $ 76,905
Available-for-Sale More than One Year, Number of Securities | Security 158 15
Available-for-Sale, Gross Unrealized Loss $ (137,232) $ (12,041)
Available-for-Sale, Estimated Fair Value $ 830,151 $ 877,344
Available-for-Sale, Number of Securities | Security 225 173
U.S. Treasury securities    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ (1,145) $ (61)
Available-for-Sale Within One Year, Estimated Fair Value $ 28,773 $ 8,391
Available-for-Sale Within One Year, Number of Securities | Security 12 2
Available-for-Sale More than One Year, Gross Unrealized Loss $ (571)  
Available-for-Sale More than One Year, Estimated Fair Value $ 4,387  
Available-for-Sale More than One Year, Number of Securities | Security 1  
Available-for-Sale, Gross Unrealized Loss $ (1,716) $ (61)
Available-for-Sale, Estimated Fair Value $ 33,160 $ 8,391
Available-for-Sale, Number of Securities | Security 13 2
Mortgage-backed securities    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ (14,222) $ (6,252)
Available-for-Sale Within One Year, Estimated Fair Value $ 104,500 $ 535,610
Available-for-Sale Within One Year, Number of Securities | Security 33 102
Available-for-Sale More than One Year, Gross Unrealized Loss $ (78,743) $ (1,654)
Available-for-Sale More than One Year, Estimated Fair Value $ 417,870 $ 59,457
Available-for-Sale More than One Year, Number of Securities | Security 105 11
Available-for-Sale, Gross Unrealized Loss $ (92,965) $ (7,906)
Available-for-Sale, Estimated Fair Value $ 522,370 $ 595,067
Available-for-Sale, Number of Securities | Security 138 113
Collateralized mortgage obligations    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ (1,526) $ (1,256)
Available-for-Sale Within One Year, Estimated Fair Value $ 25,479 $ 76,894
Available-for-Sale Within One Year, Number of Securities | Security 10 16
Available-for-Sale More than One Year, Gross Unrealized Loss $ (10,940) $ (334)
Available-for-Sale More than One Year, Estimated Fair Value $ 60,927 $ 12,548
Available-for-Sale More than One Year, Number of Securities | Security 18 3
Available-for-Sale, Gross Unrealized Loss $ (12,466) $ (1,590)
Available-for-Sale, Estimated Fair Value $ 86,406 $ 89,442
Available-for-Sale, Number of Securities | Security 28 19
Debt securities    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ (2,390) $ (1,503)
Available-for-Sale Within One Year, Estimated Fair Value $ 38,488 $ 110,996
Available-for-Sale Within One Year, Number of Securities | Security 9 21
Available-for-Sale More than One Year, Gross Unrealized Loss $ (9,880) $ (100)
Available-for-Sale More than One Year, Estimated Fair Value $ 89,146 $ 4,900
Available-for-Sale More than One Year, Number of Securities | Security 18 1
Available-for-Sale, Gross Unrealized Loss $ (12,270) $ (1,603)
Available-for-Sale, Estimated Fair Value $ 127,634 $ 115,896
Available-for-Sale, Number of Securities | Security 27 22
Total U.S. government agency and sponsored agency obligations    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ (18,138) $ (9,011)
Available-for-Sale Within One Year, Estimated Fair Value $ 168,467 $ 723,500
Available-for-Sale Within One Year, Number of Securities | Security 52 139
Available-for-Sale More than One Year, Gross Unrealized Loss $ (99,563) $ (2,088)
Available-for-Sale More than One Year, Estimated Fair Value $ 567,943 $ 76,905
Available-for-Sale More than One Year, Number of Securities | Security 141 15
Available-for-Sale, Gross Unrealized Loss $ (117,701) $ (11,099)
Available-for-Sale, Estimated Fair Value $ 736,410 $ 800,405
Available-for-Sale, Number of Securities | Security 193 154
Municipal bonds-tax exempt    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ (2,735) $ (881)
Available-for-Sale Within One Year, Estimated Fair Value $ 10,906 $ 68,548
Available-for-Sale Within One Year, Number of Securities | Security 3 17
Available-for-Sale More than One Year, Gross Unrealized Loss $ (15,080)  
Available-for-Sale More than One Year, Estimated Fair Value $ 49,675  
Available-for-Sale More than One Year, Number of Securities | Security 16  
Available-for-Sale, Gross Unrealized Loss $ (17,815) $ (881)
Available-for-Sale, Estimated Fair Value $ 60,581 $ 68,548
Available-for-Sale, Number of Securities | Security 19 17