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Securities (Additional Information) (Details)
$ in Thousands
Sep. 30, 2020
USD ($)
security
Dec. 31, 2019
USD ($)
Debt Securities, Available-for-sale [Line Items]    
Securities available-for-sale | $ $ 253,527 $ 180,905
Number of securities | security 306  
Number of securities in an unrealized loss position | security 29  
Credit Concentration Risk | Securities | Tax-exempt securities backed by the Michigan School Bond Loan Fund    
Debt Securities, Available-for-sale [Line Items]    
Number of securities | security 66  
Securities available-for-sale | $ $ 48,900  
Collateral pledged    
Debt Securities, Available-for-sale [Line Items]    
Securities pledged | $ $ 97,200 $ 27,300