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Note 10 - Fair Values of Financial Instruments - Fair Value Hierarchy of Financial Instruments (Details) - USD ($) | Mar. 31, 2018 | Dec. 31, 2017
--- | --- | ---
Debt Securities, Available-for-sale, Total |  | $ 336,988,000 | $ 335,744,000
Reported Value Measurement [Member] |  |  |
Debt Securities, Available-for-sale, Total | [1] | 336,988,000 | 335,744,000
FHLBI stock | [2] | 11,036,000 | 11,036,000
Repurchase agreements |  | 104,894,000 | 118,748,000
FHLBI advances |  | 220,000,000 | 220,000,000
Reported Value Measurement [Member] | Interest Rate Swap [Member] |  |  |
Interest rate swap | [1] | 0 | 2,000
Estimate of Fair Value Measurement [Member] |  |  |
Debt Securities, Available-for-sale, Total | [1] | 336,988,000 | 335,744,000
FHLBI stock | [2] | 11,036,000 | 11,036,000
Repurchase agreements |  | 104,894,000 | 118,748,000
FHLBI advances |  | 214,172,000 | 217,130,000
Estimate of Fair Value Measurement [Member] | Interest Rate Swap [Member] |  |  |
Interest rate swap | [1] | 0 | 2,000
Fair Value, Inputs, Level 1 [Member] | Reported Value Measurement [Member] |  |  |
Cash |  | 11,148,000 | 11,565,000
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value Measurement [Member] |  |  |
Cash |  | 11,148,000 | 11,565,000
Fair Value, Inputs, Level 2 [Member] | Reported Value Measurement [Member] |  |  |
Cash equivalents |  | 200,009,000 | 188,536,000
Loans held for sale |  | 1,864,000 | 2,553,000
Mortgage servicing rights |  | 4,899,000 | 5,106,000
Accrued interest receivable |  | 9,590,000 | 8,770,000
Deposits |  | 2,540,053,000 | 2,522,365,000
Subordinated debentures |  | 45,688,000 | 45,517,000
Accrued interest payable |  | 2,172,000 | 1,919,000
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member] |  |  |
Cash equivalents |  | 200,009,000 | 188,536,000
Loans held for sale |  | 1,864,000 | 2,553,000
Mortgage servicing rights |  | 8,223,000 | 8,373,000
Accrued interest receivable |  | 9,590,000 | 8,770,000
Deposits |  | 2,361,212,000 | 2,368,188,000
Subordinated debentures |  | 46,280,000 | 45,732,000
Accrued interest payable |  | 2,172,000 | 1,919,000
Fair Value, Inputs, Level 3 [Member] | Reported Value Measurement [Member] |  |  |
Loans, net |  | 2,529,366,000 | 2,536,498,000
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member] |  |  |
Loans, net |  | $ 2,528,622,000 | $ 2,520,063,000
[1] | See Note 11 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.

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