Annual report pursuant to Section 13 and 15(d)

Income Taxes - Additional Information (Detail)

v3.10.0.1
Income Taxes - Additional Information (Detail) - USD ($)
$ in Thousands
 12 Months Ended
Jan. 01, 2018
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Income Tax Disclosure [Abstract]        
Unrecognized tax benefits that would affect our effective tax rate if recognized   $ 202 $ 1,000 $ 1,000
Decrease in unrecognized tax benefits due to lapse of statute of limitations   837 0 0
Increase in unrecognized tax benefits       105
Accrued interest on uncertain tax benefits   10 34 33
Accrued interest related to uncertain tax positions, net of federal tax benefit   57 132 101
Income tax deductions due to excess tax benefits   37 1,800  
Valuation allowance   4,852 $ 2,750 1,031
Increase in deferred tax assets, allowance for loan losses and net operating loss carryforwards   2,100    
Operating Loss Carryforwards [Line Items]        
Change to provisional amount related to remeasurement of deferred tax assets and liabilities   1,100    
Federal [Member]        
Operating Loss Carryforwards [Line Items]        
Net operating loss carryforwards   210,700    
State [Member]        
Operating Loss Carryforwards [Line Items]        
Low income housing tax credit   204    
Central Bancorp, Inc        
Operating Loss Carryforwards [Line Items]        
Increase in deferred tax assets   $ 5,000   $ 13,900
ASU 2018-02        
Operating Loss Carryforwards [Line Items]        
Adjustment impact of adoption of Tax Act $ 399