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Note 5 - Allowance for Loan Losses (Details Textual) | 3 Months Ended | 12 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | ---
Mar. 31, 2017 | Mar. 31, 2016 | Dec. 31, 2015 USD ($) | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($) | Jun. 30, 2015 USD ($) | Dec. 31, 2014 USD ($)
Allowance for Loan Losses, Loss History Period, Number of Quarters | 16 | 16 | 8 |  |  |  |
Allowance for Credit Losses, Change in Method of Calculating Impairment |  |  |  | $ 114,144 |  | $ 1,621,424 |
Loan Balance For Reviewing High Risk Loans Minimum |  |  |  | 250,000 |  |  |
Loans and Leases Receivable, Gross |  |  | $ 758,635,595 | 765,283,855 | $ 754,283,563 |  |
Loans and Leases Receivable, Allowance |  |  | 8,603,905 | $ 7,507,508 | 8,923,293 |  | $ 8,802,316
Impaired Financing Receivable, Number of Loans Below Review Threshold |  |  |  | 149 |  |  |
Impaired Financing Receivable Recorded Investment Below Review Threshold |  |  | $ 3,744,733 | $ 4,335,524 | 4,204,156 |  |
Substandard [Member] |  |  |  |  |  |  |
Loans and Leases Receivable, Gross |  |  |  | 21,932,186 | 26,787,938 |  |
Loans Not Classified as Impaired [Member] | Substandard [Member] |  |  |  |  |  |  |
Loans and Leases Receivable, Gross |  |  |  | 9,470,621 | 10,786,699 |  |
Loans and Leases Receivable, Allowance |  |  |  | $ 1,510,868 | $ 632,706 |  |

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- Definition Number of impaired financing receivables below the $250,000 threshold for review and not individually reviewed for impairment. + References No definition available. + Details
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- Definition Amount of investment of impaired financing receivables below the $250,000 threshold for review and were not individually reviewed for impairment. + References No definition available. + Details
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- Definition Amount of allowance for credit losses related to receivables which had been measured under a general allowance for credit losses methodology that are now identified as troubled debt restructurings. + References No definition available. + Details
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- Definition Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.7(d)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SAB Topic 6.L.1) -URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74567-122707 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (b)(1)(ii) -URI http://asc.fasb.org/extlink&oid=82894903&loc=d3e15032-111544 + Details
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- Definition Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522 + Details
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