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v3.20.4

Borrowings - Additional information (Details) |  |  | 12 Months Ended |
--- | --- | --- | --- | ---
Dec. 31, 2020 USD ($) item | Feb. 24, 2020 USD ($) | Dec. 31, 2020 USD ($) item | Dec. 31, 2019 USD ($) | Dec. 31, 2018 USD ($)
Borrowings |  |  |  |  |
Threshold percentage of stockholders' equity |  |  | 10.00% |  |
Borrowings at FHLBC as percentage of total assets | 35.00% |  | 35.00% |  |
FHLBC advance amount |  |  |  |  | $ 6,700,000
Bank owned FHLBC stock | $ 3,700,000 |  | $ 3,700,000 |  |
Fair value of securities collateralized | 54,700,000 |  | 54,700,000 |  |
Principal balance of loans collateralized | 625,800,000 |  | 625,800,000 |  |
Maximum borrowing capacity |  |  |  | $ 459,500,000 |
Proceeds from term note | 20,000,000.0 | $ 20,000,000 |  |  |
Cash distribution rate of trust preferred securities (as a percent) |  | 7.80% |  |  |
Amount available for additional borrowings | 336,900,000 |  | 336,900,000 |  |
Senior notes | 44,375,000 |  | 44,375,000 | 44,270,000 |
Basis points added to reference rate (as a percent) |  | 175.00% |  |  |
Debt issuance costs |  |  |  | 1,000 | 644,000
Total borrowings | 160,521,000 |  | 160,521,000 | $ 205,870,000 |
GCFC/ABC Bank |  |  |  |  |
Borrowings |  |  |  |  |
FHLBC advance amount | $ 6,400,000 |  | $ 6,400,000 |  |
Debt Instrument, Term |  |  | 5 years 3 months | 6 years 3 months |
Debt assumed |  |  |  |  | $ 23,400,000
GCFC/ABC Bank | Maximum [Member] |  |  |  |  |
Borrowings |  |  |  |  |
Interest rate (as a percent) | 2.83% |  | 2.83% | 2.83% |
Securities Sold under Agreements to Repurchase [Member] |  |  |  |  |
Borrowings |  |  |  |  |
Carrying amount of securities secured | $ 67,000,000.0 |  | $ 67,000,000.0 | $ 48,700,000 |
Fair value of the pledged collateral | $ 94,400,000 |  | $ 94,400,000 | 70,700,000 |
Number of customers having secured balances exceeding specified percentage of stockholders equity | item | 0 |  | 0 |  |
Total borrowings | $ 66,980,000 |  | $ 66,980,000 | 48,693,000 |
Securities Sold under Agreements to Repurchase [Member] | Minimum [Member] |  |  |  |  |
Borrowings |  |  |  |  |
Maturity |  |  | 1 day |  |
Securities Sold under Agreements to Repurchase [Member] | Maximum [Member] |  |  |  |  |
Borrowings |  |  |  |  |
Maturity |  |  | 90 days |  |
Federal Home Loan Bank Advances [Member] |  |  |  |  |
Borrowings |  |  |  |  |
FHLBC advance amount | 0 |  | $ 0 | 48,500,000 |
Total borrowings |  |  |  | $ 48,500,000 |
FHLB advances at 1.44 % |  |  |  |  |
Borrowings |  |  |  |  |
Interest rate (as a percent) |  |  |  | 1.78% |
Notes Payable to Banks [Member] |  |  |  |  |
Borrowings |  |  |  |  |
Total borrowings | 23,393,000 |  | 23,393,000 | $ 6,673,000 |
Junior Subordinated Debt |  |  |  |  |
Borrowings |  |  |  |  |
Total borrowings | $ 25,773,000 |  | $ 25,773,000 | 57,734,000 |
Senior Notes. |  |  |  |  |
Borrowings |  |  |  |  |
Interest rate (as a percent) | 5.75% |  | 5.75% |  |
Senior notes | $ 44,400,000 |  | $ 44,400,000 | 44,300,000 |
Debt Instrument, Term |  |  | 10 years |  |
Interest rate term |  |  | 5 years |  |
Debt issuance costs | 625,000 |  | $ 625,000 | 730,000 |
Amortization period for deferred financing costs |  |  | 10 years |  |
Total borrowings | 44,375,000 |  | $ 44,375,000 | $ 44,270,000 |
Senior Notes. | Debt Instrument, Variable Rate Base LIBOR [Member] |  |  |  |  |
Borrowings |  |  |  |  |
Basis points added to reference rate (as a percent) |  |  |  | 385.00% |
Term note |  |  |  |  |
Borrowings |  |  |  |  |
Proceeds from term note | $ 17,000,000.0 | $ 20,000,000.0 |  |  |

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