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Note 16 - Fair Values of Financial Instruments - Fair Value Hierarchy of Financial Instruments (Details) - USD ($) | Dec. 31, 2019 | Dec. 31, 2018
--- | --- | ---
Securities available for sale |  | $ 334,655,000 | $ 337,366,000
Servicing Asset at Fair Value, Amount, Ending Balance |  | 7,400,000 | 8,400,000
Reported Value Measurement [Member] |  |  |
Securities available for sale | [1] | 334,655,000 | 337,366,000
Federal Home Loan Bank stock | [2] | 18,002,000 | 16,022,000
Estimate of Fair Value Measurement [Member] |  |  |
Securities available for sale | [1] | 334,655,000 | 337,366,000
Federal Home Loan Bank stock | [2] | 18,002,000 | 16,022,000
Fair Value, Inputs, Level 1 [Member] |  |  |
Securities available for sale |  | 0 | 0
Fair Value, Inputs, Level 1 [Member] | Reported Value Measurement [Member] |  |  |
Cash |  | 16,430,000 | 15,656,000
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value Measurement [Member] |  |  |
Cash |  | 16,430,000 | 15,656,000
Fair Value, Inputs, Level 2 [Member] | Reported Value Measurement [Member] |  |  |
Cash equivalents |  | 217,301,000 | 59,698,000
Loans held for sale |  | 4,978,000 | 1,122,000
Servicing Asset at Fair Value, Amount, Ending Balance |  | 4,652,000 | 4,436,000
Accrued interest receivable |  | 9,944,000 | 9,896,000
Deposits |  | 2,690,384,000 | 2,463,708,000
Securities sold under agreements to repurchase |  | 102,675,000 | 103,519,000
Federal Home Loan Bank advances |  | 354,000,000 | 350,000,000
Subordinated debentures |  | 46,881,000 | 46,199,000
Accrued interest payable |  | 3,949,000 | 2,249,000
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member] |  |  |
Cash equivalents |  | 217,301,000 | 59,698,000
Loans held for sale |  | 4,978,000 | 1,122,000
Servicing Asset at Fair Value, Amount, Ending Balance |  | 7,375,000 | 8,444,000
Accrued interest receivable |  | 9,944,000 | 9,896,000
Deposits |  | 2,600,452,000 | 2,471,617,000
Securities sold under agreements to repurchase |  | 102,675,000 | 103,519,000
Federal Home Loan Bank advances |  | 361,887,000 | 348,428,000
Subordinated debentures |  | 46,140,000 | 46,543,000
Accrued interest payable |  | 3,949,000 | 2,249,000
Fair Value, Inputs, Level 3 [Member] | Reported Value Measurement [Member] |  |  |
Loans, net |  | 2,827,800,000 | 2,729,583,000
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member] |  |  |
Loans, net |  | $ 2,887,168,000 | $ 2,711,687,000
[1] | See Note 17 for a description of the fair value hierarchy as well as a disclosure of levels for classes of financial assets and liabilities.
[2] | It is not practical to determine the fair value of FHLBI stock due to transferability restrictions; therefore, fair value is estimated at carrying amount.

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