Quarterly report pursuant to Section 13 or 15(d)

Borrowings - Additional Information (Detail)

v3.20.2
Borrowings - Additional Information (Detail) - USD ($)
 3 Months Ended 6 Months Ended
Jun. 30, 2020
Jun. 30, 2019
Jun. 30, 2020
Jun. 30, 2019
Dec. 31, 2019
Debt Instrument [Line Items]          
Overnight advances from federal home loan banks $ 0   $ 0   $ 15,000,000.0
Advances from the FHLB $ 150,000,000.0   $ 150,000,000.0   $ 75,000,000.0
Weighted average interest rate of outstanding advances (percent) 1.63%   1.63%   1.71%
Interest expense on borrowings $ 760,000 $ 0 $ 1,256,000 $ 72,000  
Weighted average interest rate of overnight advances (percent)         1.66%
Outstanding borrowings         $ 0
Pledged loans receivable, carrying value 2,400,000,000   2,400,000,000   1,400,000,000
Remaining available borrowing capacity 1,500,000,000   1,500,000,000    
FHLB statutory lending limit 1,400,000,000   1,400,000,000   878,400,000
Loans pledged with FRB 50,000,000.0   50,000,000.0   30,200,000
Borrowing capacity through Fed Discount Window 47,900,000   47,900,000   $ 29,600,000
Paycheck Protection Program          
Debt Instrument [Line Items]          
Advances from Federal Reserve Bank $ 101,800,000   $ 101,800,000    
Advances from Federal Reserve Bank, percentage 0.35%   0.35%