Quarterly report pursuant to Section 13 or 15(d)

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

v3.20.2
Securities - Summary of Investment Securities Available for Sale (Detail) - USD ($)
$ in Thousands
Jun. 30, 2020
Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost $ 655,500 $ 629,725
Gross Unrealized Gain 1,101 5,553
Gross Unrealized Loss (630) (801)
Estimated Fair Value 655,971 634,477
U.S. Treasury securities    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 44,982 34,947
Gross Unrealized Gain 280 259
Estimated Fair Value 45,262 35,206
Mortgage-backed securities    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 413,278 406,813
Gross Unrealized Gain 422 4,334
Gross Unrealized Loss (437) (347)
Estimated Fair Value 413,263 410,800
Collateralized mortgage obligations    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 120,080 164,232
Gross Unrealized Gain 390 792
Gross Unrealized Loss (176) (432)
Estimated Fair Value 120,294 164,592
Debt securities    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 77,160 23,733
Gross Unrealized Gain 9 168
Gross Unrealized Loss (17) (22)
Estimated Fair Value 77,152 23,879
Total U.S. government agency and sponsored agency obligations    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 610,518 594,778
Gross Unrealized Gain 821 5,294
Gross Unrealized Loss (630) (801)
Estimated Fair Value $ 610,709 $ 599,271