Quarterly report pursuant to Section 13 or 15(d)

Securities - Additional Information (Detail)

v3.19.3
Securities - Additional Information (Detail) - USD ($)
 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2019
Jun. 30, 2018
Mar. 31, 2018
Jun. 30, 2019
Jun. 30, 2018
Dec. 31, 2018
Jan. 01, 2018
Debt Securities, Available-for-sale [Line Items]              
Impairment charges on securities in continuous unrealized loss position for 12 months or longer       $ 0   $ 0  
Net gain (loss) in earnings resulting from sale of securities $ 570,000 $ 67,000   1,300,000 $ (361,000)    
Net unrealized gains (losses) recorded in comprehensive income 792,000 $ 95,000   586,000 $ 95,000    
Gross realized gains included in earnings       634,000      
Reduction in securities available for sale (639,995,000)     (639,995,000)   (574,908,000)  
Reduction to retained earnings (100,021,000)     (100,021,000)   (97,539,000)  
Increase in net deferred tax asset 23,200,000     23,200,000   27,400,000  
Gross realized losses included in earnings     $ 957,000        
Available for sale securities pledged as collateral $ 30,200,000     $ 30,200,000   $ 29,900,000  
ASU 2016-01              
Debt Securities, Available-for-sale [Line Items]              
Reduction in securities available for sale             $ 529,000
Reduction to retained earnings             382,000
Increase in net deferred tax asset             $ 147,000