Quarterly report pursuant to Section 13 or 15(d)

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

v3.20.1
Securities - Summary of Investment Securities Available for Sale (Detail) - USD ($)
$ in Thousands
Mar. 31, 2020
Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost $ 605,530 $ 629,725
Gross Unrealized Gain 16,708 5,553
Gross Unrealized Loss (32) (801)
Estimated Fair Value 622,206 634,477
U.S. Treasury securities    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 24,988 34,947
Gross Unrealized Gain 420 259
Estimated Fair Value 25,408 35,206
Mortgage-backed securities    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 413,350 406,813
Gross Unrealized Gain 12,023 4,334
Gross Unrealized Loss (17) (347)
Estimated Fair Value 425,356 410,800
Collateralized mortgage obligations    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 150,950 164,232
Gross Unrealized Gain 3,890 792
Gross Unrealized Loss (15) (432)
Estimated Fair Value 154,825 164,592
Debt securities    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 16,242 23,733
Gross Unrealized Gain 375 168
Gross Unrealized Loss   (22)
Estimated Fair Value 16,617 23,879
Total U.S. government agency and sponsored agency obligations    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 580,542 594,778
Gross Unrealized Gain 16,288 5,294
Gross Unrealized Loss (32) (801)
Estimated Fair Value $ 596,798 $ 599,271