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
Sep. 30, 2019
Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost $ 616,604 $ 583,444
Gross Unrealized Gain 5,940 401
Gross Unrealized Loss (729) (8,937)
Estimated Fair Value 621,815 574,908
U.S. Treasury securities    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 39,877 39,768
Gross Unrealized Gain 292 69
Gross Unrealized Loss 0 (7)
Estimated Fair Value 40,169 39,830
Mortgage-backed securities    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 395,486 300,957
Gross Unrealized Gain 4,224 61
Gross Unrealized Loss (236) (5,984)
Estimated Fair Value 399,474 295,034
Collateralized mortgage obligations    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 164,267 124,550
Gross Unrealized Gain 1,216 74
Gross Unrealized Loss (484) (2,332)
Estimated Fair Value 164,999 122,292
Debt securities    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 16,974 7,499
Gross Unrealized Gain 208 0
Gross Unrealized Loss (9) (97)
Estimated Fair Value 17,173 7,402
Total U.S. government agency and sponsored agency obligations    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 576,727 433,006
Gross Unrealized Gain 5,648 135
Gross Unrealized Loss (729) (8,413)
Estimated Fair Value $ 581,646 424,728
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