Annual report pursuant to Section 13 and 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)

v3.20.4
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
Dec. 31, 2020
USD ($)
Security
Dec. 31, 2019
USD ($)
Security
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ (406) $ (318)
Available-for-Sale Within One Year, Estimated Fair Value $ 178,681 $ 100,916
Available-for-Sale Within One Year, Number of Securities | Security 32 33
Available-for-Sale More than One Year, Gross Unrealized Loss   $ (483)
Available-for-Sale More than One Year, Estimated Fair Value   $ 61,690
Available-for-Sale More than One Year, Number of Securities | Security   51
Available-for-Sale, Gross Unrealized Loss $ (406) $ (801)
Available-for-Sale, Estimated Fair Value $ 178,681 $ 162,606
Available-for-Sale, Number of Securities | Security 32 84
Mortgage-backed securities    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ (188) $ (186)
Available-for-Sale Within One Year, Estimated Fair Value $ 76,023 $ 51,261
Available-for-Sale Within One Year, Number of Securities | Security 10 17
Available-for-Sale More than One Year, Gross Unrealized Loss   $ (160)
Available-for-Sale More than One Year, Estimated Fair Value   $ 18,757
Available-for-Sale More than One Year, Number of Securities | Security   14
Available-for-Sale, Gross Unrealized Loss $ (188) $ (346)
Available-for-Sale, Estimated Fair Value $ 76,023 $ 70,018
Available-for-Sale, Number of Securities | Security 10 31
Collateralized mortgage obligations    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ (217) $ (112)
Available-for-Sale Within One Year, Estimated Fair Value $ 97,659 $ 41,419
Available-for-Sale Within One Year, Number of Securities | Security 21 14
Available-for-Sale More than One Year, Gross Unrealized Loss   $ (320)
Available-for-Sale More than One Year, Estimated Fair Value   $ 39,936
Available-for-Sale More than One Year, Number of Securities | Security   36
Available-for-Sale, Gross Unrealized Loss $ (217) $ (432)
Available-for-Sale, Estimated Fair Value $ 97,659 $ 81,355
Available-for-Sale, Number of Securities | Security 21 50
Debt securities    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ (1) $ (20)
Available-for-Sale Within One Year, Estimated Fair Value $ 4,999 $ 8,236
Available-for-Sale Within One Year, Number of Securities | Security 1 2
Available-for-Sale More than One Year, Gross Unrealized Loss   $ (3)
Available-for-Sale More than One Year, Estimated Fair Value   $ 2,997
Available-for-Sale More than One Year, Number of Securities | Security   1
Available-for-Sale, Gross Unrealized Loss $ (1) $ (23)
Available-for-Sale, Estimated Fair Value $ 4,999 $ 11,233
Available-for-Sale, Number of Securities | Security 1 3
Total U.S. government agency and sponsored agency obligations    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ (406) $ (318)
Available-for-Sale Within One Year, Estimated Fair Value $ 178,681 $ 100,916
Available-for-Sale Within One Year, Number of Securities | Security 32 33
Available-for-Sale More than One Year, Gross Unrealized Loss   $ (483)
Available-for-Sale More than One Year, Estimated Fair Value   $ 61,690
Available-for-Sale More than One Year, Number of Securities | Security   51
Available-for-Sale, Gross Unrealized Loss $ (406) $ (801)
Available-for-Sale, Estimated Fair Value $ 178,681 $ 162,606
Available-for-Sale, Number of Securities | Security 32 84