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Summary of Significant Accounting Policies - Additional Information (Details) $ in Thousands |  | 12 Months Ended |
--- | --- | --- | ---
Feb. 26, 2020 shares | Dec. 31, 2019 USD ($) | Dec. 31, 2019 USD ($) shares | Dec. 31, 2019 USD ($) | Dec. 31, 2019 USD ($) | Dec. 31, 2019 USD ($) Segment | Dec. 31, 2018 USD ($) shares | Sep. 30, 2019 USD ($)
Finite Lived Intangible Assets [Line Items] |  |  |  |  |  |  |  |
Maximum Maturity Period For Cash Equivalents |  | 90 days |  |  |  |  |  |
Number Of Investment Portfolios |  |  |  |  | 3 |  |  |
Number of Securities Held as Trading Securities |  |  |  |  | 0 |  |  |
Number of Reportable Segments |  |  |  |  | 2 | 2 |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | shares |  |  | 68,150 |  |  |  | 62,150 |
Operating lease, right-of-use asset |  | $ 3,543 | $ 3,543 | $ 3,543 | $ 3,543 | $ 3,543 |  |
Operating lease, liability |  | 3,573 | 3,573 | 3,573 | 3,573 | 3,573 |  |
Revenue, remaining performance obligation, amount |  | 0 | 0 | 0 | 0 | 0 |  |
Contract with customer, liability, total |  | $ 0 | $ 0 | 0 | $ 0 | $ 0 |  |
Service and Other Charges on Deposit Accounts, Mortgage Fees From Secondary Market Transactions at The Bank ATM Fee Income and Other Noninterest Income [Member] |  |  |  |  |  |  |  |
Finite Lived Intangible Assets [Line Items] |  |  |  |  |  |  |  |
Revenue from Contract with Customer, Including Assessed Tax |  |  |  | $ 3,400 |  |  | $ 3,200 |
Accounting Standards Update 2016-02 [Member] |  |  |  |  |  |  |  |
Finite Lived Intangible Assets [Line Items] |  |  |  |  |  |  |  |
Operating lease, right-of-use asset |  |  |  |  |  |  |  | $ 3,500
Operating lease, liability |  |  |  |  |  |  |  | $ 3,600
Non-qualified Stock Options [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |
Finite Lived Intangible Assets [Line Items] |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | shares | 9,200 |  |  |  |  |  |  |
Restricted Stock [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |
Finite Lived Intangible Assets [Line Items] |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted | shares | 24,660 |  |  |  |  |  |  |
Core Deposits [Member] |  |  |  |  |  |  |  |
Finite Lived Intangible Assets [Line Items] |  |  |  |  |  |  |  |
Finite-Lived Intangible Asset, Useful Life |  | 7 years |  |  |  |  | 7 years |

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