Note 17 - Assets and Liabilities Measured and Reported at Fair Value - Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($)	Jun. 30, 2016	Dec. 31, 2015
US Government-sponsored Enterprises Debt Securities [Member] \| Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Fair value
US Government-sponsored Enterprises Debt Securities [Member] \| Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair value	333,826,000	251,893,000
US Government-sponsored Enterprises Debt Securities [Member] \| Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Fair value
US Government-sponsored Enterprises Debt Securities [Member] \| Fair Value, Measurements, Recurring [Member]
Fair value	333,826,000	251,893,000
US Government-sponsored Enterprises Debt Securities [Member]
Fair value	333,826,000	251,893,000
US Treasury and Government [Member] \| Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Fair value		80,000,000
US Treasury and Government [Member] \| Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair value
US Treasury and Government [Member] \| Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Fair value
US Treasury and Government [Member] \| Fair Value, Measurements, Recurring [Member]
Fair value		80,000,000
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Fair value
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair value	170,703,000	169,628,000
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Fair value
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| Fair Value, Measurements, Recurring [Member]
Fair value	170,703,000	169,628,000
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Fair value	170,703,000	169,628,000
US States and Political Subdivisions Debt Securities [Member] \| Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Fair value
US States and Political Subdivisions Debt Securities [Member] \| Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair value	62,021,000	63,702,000
US States and Political Subdivisions Debt Securities [Member] \| Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Fair value
US States and Political Subdivisions Debt Securities [Member] \| Fair Value, Measurements, Recurring [Member]
Fair value	62,021,000	63,702,000
US States and Political Subdivisions Debt Securities [Member]
Fair value	62,021,000	63,702,000
Common Stock [Member] \| Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Fair value	757,000	653,000
Common Stock [Member] \| Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair value
Common Stock [Member] \| Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Fair value
Common Stock [Member] \| Fair Value, Measurements, Recurring [Member]
Fair value	757,000	653,000
Common Stock [Member]
Fair value	757,000	653,000
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Fair value	757,000	80,653,000
Interest rate swaps
Total assets	757,000	80,653,000
Interest rate swaps
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair value	566,550,000	485,223,000
Interest rate swaps	1,282,000	461,000
Total assets	567,832,000	485,684,000
Interest rate swaps	2,048,000	554,000
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Fair value
Interest rate swaps
Total assets	0	0
Interest rate swaps
Fair Value, Measurements, Recurring [Member]
Fair value	567,307,000	565,876,000
Interest rate swaps	1,282,000	461,000
Total assets	568,589,000	566,337,000
Interest rate swaps	2,048,000	554,000
Fair value	$ 567,307,000	$ 565,876,000

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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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=65884222&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=73527792&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=66010992&loc=d3e26610-111562

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- Definition

Fair value as of the balance sheet date of interest rate derivative assets, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13433-108611

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- Definition

Fair value as of the balance sheet date of interest rate derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as liabilities.

+ References

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