XML 43 R55.htm IDEA: XBRL DOCUMENT v3.20.1
Securities - Additional Information (Details)
3 Months Ended
Mar. 31, 2020
USD ($)
Security
Mar. 31, 2019
USD ($)
Dec. 31, 2019
USD ($)
Schedule Of Investments [Line Items]      
Trading securities $ 0   $ 0
Net gains or (losses) reclassified from accumulated other comprehensive income (loss) into earnings 1,400,000 $ 0  
Investment securities posted as collateral 1,100,000,000   552,400,000
Carrying amount of securities pledged as collateral $ 369,700,000   $ 301,100,000
Minimum      
Schedule Of Investments [Line Items]      
Percentage of shareholders equity for which securities holdings exceeds for no issuer other than U.S. Government and agencies 10.00%   10.00%
Federal Home Loan Bank Advances      
Schedule Of Investments [Line Items]      
Carrying amount of securities pledged as collateral $ 0   $ 0
Public Fund Deposits      
Schedule Of Investments [Line Items]      
Carrying amount of securities pledged as collateral 299,300,000   240,400,000
Customer Repurchase Agreements      
Schedule Of Investments [Line Items]      
Carrying amount of securities pledged as collateral $ 65,300,000   $ 55,700,000
Available-for-sale Securities      
Schedule Of Investments [Line Items]      
Investment securities with unrealized losses | Security 50    
Held-to-maturity Securities      
Schedule Of Investments [Line Items]      
Investment securities with unrealized losses | Security 0