XML 128 R111.htm IDEA: XBRL DOCUMENT v3.20.4
Income Taxes - Additional Information (Detail) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Operating Loss Carryforwards [Line Items]      
Accumulated other comprehensive income, deferred tax (benefit) expense $ 5,200 $ 6,600 $ (2,400)
Accumulated other comprehensive income, a deferred tax expense (benefit) 1,400 $ (463) $ 379
Retained earnings amount for which no provision for income tax has been made 51,800    
Unrecognized tax liability 13,400    
Federal      
Operating Loss Carryforwards [Line Items]      
Operating loss carryforwards, limitations on use 197    
Beacon Trust      
Operating Loss Carryforwards [Line Items]      
Unused capital loss carryforwards $ 1,300