Quarterly report pursuant to Section 13 or 15(d)

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

v3.19.3
Securities - Summary of Investment Securities Available for Sale (Detail) - USD ($)
$ in Thousands
Jun. 30, 2019
Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost $ 636,657 $ 583,444
Gross Unrealized Gain 4,622 401
Gross Unrealized Loss (1,284) (8,937)
Estimated Fair Value 639,995 574,908
U.S. Treasury securities    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 49,728 39,768
Gross Unrealized Gain 334 69
Gross Unrealized Loss 0 (7)
Estimated Fair Value 50,062 39,830
Mortgage-backed securities    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 400,656 300,957
Gross Unrealized Gain 3,013 61
Gross Unrealized Loss (685) (5,984)
Estimated Fair Value 402,984 295,034
Collateralized mortgage obligations    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 167,312 124,550
Gross Unrealized Gain 1,081 74
Gross Unrealized Loss (580) (2,332)
Estimated Fair Value 167,813 122,292
Debt securities    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 18,961 7,499
Gross Unrealized Gain 194 0
Gross Unrealized Loss (19) (97)
Estimated Fair Value 19,136 7,402
Total U.S. government agency and sponsored agency obligations    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 586,929 433,006
Gross Unrealized Gain 4,288 135
Gross Unrealized Loss (1,284) (8,413)
Estimated Fair Value $ 589,933 424,728
Municipal bonds-tax exempt    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost   110,670
Gross Unrealized Gain   197
Gross Unrealized Loss   (517)
Estimated Fair Value   $ 110,350