XML 91 R80.htm IDEA: XBRL DOCUMENT v3.21.1
Borrowings and Subordinated Debentures - Narrative (Details) - USD ($)
3 Months Ended
Mar. 31, 2021
Dec. 31, 2020
Unused Lines of Credit    
Debt Instrument [Line Items]    
Amount outstanding $ 0 $ 0
Current borrowing capacity 180,000,000.0  
Unused commitment fees 0  
AFX short-term borrowings    
Debt Instrument [Line Items]    
Amount outstanding 0 0
Federal Reserve Bank Advances    
Debt Instrument [Line Items]    
Loans pledged as collateral 1,800,000,000  
Amount outstanding 0 0
Federal Reserve Bank Advances | FHLB secured advances    
Debt Instrument [Line Items]    
Borrowing capacity description 1,400,000,000  
Federal Home Loan Bank of San Francisco    
Debt Instrument [Line Items]    
Loans pledged as collateral 5,000,000,000.0  
Federal Home Loan Bank of San Francisco | FHLB secured advances    
Debt Instrument [Line Items]    
Borrowing capacity description 3,500,000,000  
Current outstanding 5,000,000 5,000,000
Federal Home Loan Bank of San Francisco | FHLB unsecured overnight advance    
Debt Instrument [Line Items]    
Current outstanding 0 $ 0
Federal Home Loan Bank of San Francisco | Unused Lines of Credit    
Debt Instrument [Line Items]    
Borrowing capacity description $ 112,000,000.0