Annual report pursuant to Section 13 and 15(d)

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

v3.20.4
Securities - Summary of Investment Securities Available for Sale (Detail) - USD ($)
$ in Thousands
Dec. 31, 2020
Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost $ 749,458 $ 629,725
Gross Unrealized Gain 4,729 5,553
Gross Unrealized Loss (406) (801)
Estimated Fair Value 753,781 634,477
U.S. Treasury securities    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 9,997 34,946
Gross Unrealized Gain 135 259
Estimated Fair Value 10,132 35,206
Mortgage-backed securities    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 515,169 406,813
Gross Unrealized Gain 4,260 4,334
Gross Unrealized Loss (188) (347)
Estimated Fair Value 519,241 410,801
Collateralized mortgage obligations    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 133,632 164,232
Gross Unrealized Gain 186 792
Gross Unrealized Loss (217) (432)
Estimated Fair Value 133,601 164,592
Debt securities    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 90,660 23,733
Gross Unrealized Gain 148 168
Gross Unrealized Loss (1) (22)
Estimated Fair Value 90,807 23,878
Total U.S. government agency and sponsored agency obligations    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 739,461 594,778
Gross Unrealized Gain 4,594 5,294
Gross Unrealized Loss (406) (801)
Estimated Fair Value $ 743,649 $ 599,271