Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020
Fair Values of Financial Instruments
Proceeds from sales of FHLBC/FRBC stock	$ 6,875	$ 6,754
Financial assets:
Cash and due from banks	34,096		$ 24,306
Interest bearing deposits with financial institutions	16,536		305,597
Securities available-for-sale	484,648		496,178
FHLBC and FRBC Stock	9,917		9,917
Bank-owned life insurance	61,763		63,102
Financial liabilities:
Noninterest bearing deposits	669,795		909,505
Other short-term borrowings	48,500
Junior subordinated debentures	57,734		25,773
Reported Value Measurement [Member]
Financial assets:
Cash and due from banks	34,096		24,306
Interest bearing deposits with financial institutions	16,536		305,597
Securities available-for-sale	484,648		496,178
FHLBC and FRBC Stock	9,917		9,917
Loans held for sale	3,061		12,611
Net loans	1,911,023		2,000,996
Interest rate swap agreements	2,771		9,388
Interest rate lock commitments and forward contracts	250		840
Interest receivable on securities and loans	9,697		9,698
Financial liabilities:
Noninterest bearing deposits	669,795		909,505
Interest bearing deposits	1,456,954		1,627,568
Securities sold under repurchase agreements	48,693		66,980
Other short-term borrowings	48,500
Junior subordinated debentures	57,734		25,773
Senior notes	44,270		44,375
Note payable and other borrowings	6,673		23,393
Interest rate swap agreements	5,921		13,071
Interest payable on deposits and borrowings	1,079		418
Estimate of Fair Value Measurement [Member]
Financial assets:
Cash and due from banks	34,096		24,306
Interest bearing deposits with financial institutions	16,536		305,597
Securities available-for-sale	484,648		496,178
FHLBC and FRBC Stock	9,917		9,917
Loans held for sale	3,061		12,611
Net loans	1,915,531		2,009,773
Interest rate swap agreements	2,771		9,388
Interest rate lock commitments and forward contracts	250		840
Interest receivable on securities and loans	9,697		9,698
Financial liabilities:
Noninterest bearing deposits	669,795		909,505
Interest bearing deposits	1,457,832		1,630,109
Securities sold under repurchase agreements	48,693		66,980
Other short-term borrowings	48,500
Junior subordinated debentures	51,188		14,658
Senior notes	46,269		44,600
Note payable and other borrowings	7,003		24,043
Interest rate swap agreements	5,921		13,071
Interest payable on deposits and borrowings	1,079		418
Fair Value, Inputs, Level 1 [Member]
Financial assets:
Cash and due from banks	34,096		24,306
Interest bearing deposits with financial institutions	16,536		305,597
Securities available-for-sale	4,036		4,117
Financial liabilities:
Noninterest bearing deposits	669,795		909,505
Junior subordinated debentures	33,614
Senior notes	46,269		44,600
Fair Value, Inputs, Level 2 [Member]
Financial assets:
Securities available-for-sale	475,193		487,742
FHLBC and FRBC Stock	9,917		9,917
Loans held for sale	3,061		12,611
Interest rate swap agreements	2,771		9,388
Interest rate lock commitments and forward contracts	250		840
Interest receivable on securities and loans	9,697		9,698
Financial liabilities:
Interest bearing deposits	1,457,832		1,630,109
Securities sold under repurchase agreements	48,693		66,980
Other short-term borrowings	48,500
Junior subordinated debentures	17,574		14,658
Note payable and other borrowings	7,003		24,043
Interest rate swap agreements	5,921		13,071
Interest payable on deposits and borrowings	1,079		418
Fair Value, Inputs, Level 3 [Member]
Financial assets:
Securities available-for-sale	5,419		4,319
Net loans	$ 1,915,531		$ 2,009,773

The value of interest rate lock commitments and forward contracts.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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The carrying amount of a life insurance policy on an officer, executive or employee for which the reporting entity (a bank) is entitled to proceeds from the policy upon death of the insured or surrender of the insurance policy.

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For banks and other depository institutions: Includes cash on hand (currency and coin), cash items in process of collection, noninterest bearing deposits due from other financial institutions (including corporate credit unions), and noninterest bearing balances with the Federal Reserve Banks, Federal Home Loan Banks and central banks.

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Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Fair value of subordinated debt obligations including, but not limited to, subordinated loan, subordinated bond, subordinated debenture or junior debt.

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Amount of Federal Home Loan Bank (FHLB) and Federal Reserve Bank stock.

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The aggregate of all domestic and foreign interest-bearing deposit liabilities.

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For banks and other depository institutions (including Federal Reserve Banks, if applicable): Interest-bearing deposits in other financial institutions for relatively short periods of time including, for example, certificates of deposits, which are presented separately from cash on the balance sheet.

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Amount of interest payable on debt, including, but not limited to, trade payables.

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Carrying amount as of the balance sheet date of interest earned but not received. Also called accrued interest or accrued interest receivable.

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Including the current and noncurrent portions, the carrying value of junior subordinated long-term debt owed to unconsolidated subsidiary trusts as of the balance sheet date. Such debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets and was initially scheduled to be repaid after one year or beyond the normal operating cycle if longer.

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Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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The aggregate amount of all domestic and foreign noninterest-bearing deposits liabilities held by the entity.

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Amount of borrowings classified as other, maturing within one year or the normal operating cycle, if longer.

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Amount of cash inflow from sale of Federal Home Loan Bank (FHLB) stock.

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Fair value portion of securities that an entity sells and agrees to repurchase at a specified date for a specified price.

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