Quarterly report pursuant to Section 13 or 15(d)

Securities - Summary of Investment Securities Available for Sale (Detail)

v3.21.1
Securities - Summary of Investment Securities Available for Sale (Detail) - USD ($)
$ in Thousands
Mar. 31, 2021
Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost $ 787,675 $ 749,458
Gross Unrealized Gain 340 4,729
Gross Unrealized Loss (7,901) (406)
Estimated Fair Value 780,114 753,781
U.S. Treasury securities    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 9,998 9,997
Gross Unrealized Gain 77 135
Estimated Fair Value 10,075 10,132
Mortgage-backed securities    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 579,209 515,169
Gross Unrealized Gain 87 4,260
Gross Unrealized Loss (7,216) (188)
Estimated Fair Value 572,080 519,241
Collateralized mortgage obligations    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 112,808 133,632
Gross Unrealized Gain 145 186
Gross Unrealized Loss (210) (217)
Estimated Fair Value 112,743 133,601
Debt securities    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 85,660 90,660
Gross Unrealized Gain 31 148
Gross Unrealized Loss (475) (1)
Estimated Fair Value 85,216 90,807
Total U.S. government agency and sponsored agency obligations    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 777,677 739,461
Gross Unrealized Gain 263 4,594
Gross Unrealized Loss (7,901) (406)
Estimated Fair Value $ 770,039 $ 743,649