Note 11 - Fair Values (Details Textual) - USD ($)	9 Months Ended
Sep. 30, 2017	Dec. 31, 2016
Available-for-sale Securities	$ 330,090,000	$ 328,060,000
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group, Mortgage	$ 4,100,000	1,000,000
Real Estate Dependent Loans and Foreclosed Assets Estimated Selling Costs [Member]
Fair Value Inputs, Discount Factor	10.00%
Real Estate Dependent Loans and Foreclosed Assets [Member] \| Commercial Real Estate [Member] \| Minimum [Member]
Fair Value Inputs, Discount Factor	15.00%
Real Estate Dependent Loans and Foreclosed Assets [Member] \| Commercial Real Estate [Member] \| Maximum [Member]
Fair Value Inputs, Discount Factor	25.00%
Real Estate Dependent Loans and Foreclosed Assets [Member] \| Residential Real Estate [Member] \| Minimum [Member]
Fair Value Inputs, Discount Factor	25.00%
Real Estate Dependent Loans and Foreclosed Assets [Member] \| Residential Real Estate [Member] \| Maximum [Member]
Fair Value Inputs, Discount Factor	50.00%
Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities	$ 0
Available-for-sale Securities [Member]
Valuation Allowances and Reserves, Balance	$ 0	$ 0

Discount factor used to further reduce the balance sheet carrying amount of property or other assets.

No definition available.

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=75030427&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82896770&loc=d3e26610-111562

+ Details

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- Definition

Amount, after allowance for bad debt, of mortgage loan receivables held-for-sale that are not part of a disposal group. Excludes loans and leases covered under loss sharing agreements and loans classified as debt securities.

+ 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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- Definition

Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09)
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

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- Details

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