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Borrowings - Additional information (Details) |  | 3 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | --- | ---
Feb. 24, 2020 USD ($) | Jun. 30, 2022 USD ($) | Jun. 30, 2021 USD ($) | Dec. 31, 2016 | Dec. 31, 2022 USD ($) item | Dec. 31, 2021 USD ($) | Dec. 31, 2018 USD ($)
Borrowings |  |  |  |  |  |  |
Securities available-for-sale, at fair value |  |  |  |  | $ 1,539,359,000 | $ 1,693,632,000 |
Threshold percentage of stockholders' equity |  |  |  |  | 10.00% |  |
Borrowings at FHLBC as percentage of total assets |  |  |  |  | 35.00% |  |
FHLBC stock |  |  |  |  | $ 5,600,000 | 7,100,000 |
Federal Home Loan Bank Chicago ("FHLBC") and Federal Reserve Bank Chicago ("FRBC") stock |  |  |  |  | 20,530,000 | 13,257,000 |
Proceeds from term note | $ 30,000,000.0 |  |  |  |  |  |
Cash distribution rate of trust preferred securities (as a percent) | 7.80% |  |  |  |  |  |
Senior notes |  |  |  |  | 44,585,000 | 44,480,000 |
Basis points added to reference rate (as a percent) | 175.00% |  |  |  |  |  |
Outstanding, net of deferred issuance costs |  |  |  |  | 59,300,000 | 59,200,000 |
Debt issuance costs |  |  |  |  | 1,000 | 1,000 |
Total borrowings |  |  |  |  | 260,811,000 | 198,876,000 |
Asset Pledged as Collateral with Right | Securities sold under repurchase agreements |  |  |  |  |  |  |
Borrowings |  |  |  |  |  |  |
Investment securities pledged with financial institutions, dollars |  |  |  |  | 71,400,000 | 113,000,000.0 |
GCFC/ABC Bank |  |  |  |  |  |  |
Borrowings |  |  |  |  |  |  |
Debt assumed |  |  |  |  |  |  | $ 23,400,000
Balance of borrowings paid off |  | $ 5,900,000 |  |  |  |  |
Securities sold under repurchase agreements |  |  |  |  |  |  |
Borrowings |  |  |  |  |  |  |
Investment securities pledged with financial institutions, dollars |  |  |  |  | $ 32,200,000 | 50,300,000 |
Number of customers having secured balances exceeding specified percentage of stockholders equity | item |  |  |  |  | 0 |  |
Total borrowings |  |  |  |  | $ 32,156,000 | 50,337,000 |
Securities sold under repurchase agreements | Minimum |  |  |  |  |  |  |
Borrowings |  |  |  |  |  |  |
Maturity |  |  |  |  | 1 day |  |
Securities sold under repurchase agreements | Maximum |  |  |  |  |  |  |
Borrowings |  |  |  |  |  |  |
Maturity |  |  |  |  | 90 days |  |
Federal Home Loan Bank Advances |  |  |  |  |  |  |
Borrowings |  |  |  |  |  |  |
Borrowings at FHLBC as percentage of book value of certain mortgage loans |  |  |  |  | 60.00% |  |
FHLBC advance amount |  |  |  |  | $ 90,000,000.0 | 0 |
FHLBC stock |  |  |  |  | 5,600,000 | 7,100,000 |
Principal balance of loans collateralized |  |  |  |  | 969,100,000 | 572,600,000 |
Maximum borrowing capacity |  |  |  |  |  | 603,100,000 |
Amount available for additional borrowings |  |  |  |  | 513,100,000 |  |
Subordinated debentures |  |  |  |  |  |  |
Borrowings |  |  |  |  |  |  |
Total borrowings |  |  |  |  | 59,297,000 | 59,212,000 |
Notes Payable to Banks [Member] |  |  |  |  |  |  |
Borrowings |  |  |  |  |  |  |
Total borrowings |  |  |  |  | 9,000,000 | 19,074,000 |
Junior subordinated debentures |  |  |  |  |  |  |
Borrowings |  |  |  |  |  |  |
Total borrowings |  |  |  |  | $ 25,773,000 | 25,773,000 |
Senior Notes [Member] |  |  |  |  |  |  |
Borrowings |  |  |  |  |  |  |
Interest rate (as a percent) |  |  |  |  | 5.75% |  |
Senior notes |  |  |  |  | $ 44,600,000 | 44,500,000 |
Debt Instrument, Term |  |  |  | 10 years |  |  |
Interest rate term |  |  |  |  | 5 years |  |
Effective interest rate |  |  |  |  | 8.62% |  |
Debt issuance costs |  |  |  |  | $ 415,000 | 520,000 |
Amortization period for deferred financing costs |  |  |  |  | 10 years |  |
Total borrowings |  |  |  |  | $ 44,585,000 | $ 44,480,000 |
Debt instrument redemption price, percentage |  |  |  |  | 100.00% |  |
Senior Notes [Member] | Debt Instrument, Variable Rate Base LIBOR [Member] |  |  |  |  |  |  |
Borrowings |  |  |  |  |  |  |
Basis points added to reference rate (as a percent) |  |  |  |  | 385.00% |  |
Term Debt |  |  |  |  |  |  |
Borrowings |  |  |  |  |  |  |
Proceeds from term note | $ 20,000,000.0 |  |  |  | $ 9,000,000.0 |  |
Effective interest rate |  |  |  |  | 6.14% |  |
Debt term |  |  |  |  | 3 years |  |
Subordinated Notes Due 2031 |  |  |  |  |  |  |
Borrowings |  |  |  |  |  |  |
Interest rate (as a percent) |  |  | 3.50% |  |  |  |
Face amount |  |  | $ 60,000,000.0 |  |  |  |
Subordinated Notes Due 2031 | Three Months Secured Overnight Financing Rate |  |  |  |  |  |  |
Borrowings |  |  |  |  |  |  |
Basis points added to reference rate (as a percent) |  |  | 2.73% |  |  |  |

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