Note 6 - Mortgage Loan Servicing (Details) - Activity for Capitalized Mortgage Loan Servicing Rights (USD $)	12 Months Ended
Dec. 31, 2014
Servicing Assets at Fair Value [Line Items]
Balance at January 1, 2014	$ 0us-gaap_ServicingAssetAtAmortizedValue
Additions	575,000
Amortized to expense	(1,252,000)
Balance at December 31, 2014	6,712,000us-gaap_ServicingAssetAtAmortizedValue
Firstbank Corporation [Member]
Servicing Assets at Fair Value [Line Items]
Additions	$ 7,389,000

Amortized amount of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 50

-Section 25

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-URI http://asc.fasb.org/extlink&oid=7524895&loc=d3e120260-111741

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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Amount of additions from purchases, assumption or transfer to contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 50

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Amount of amortization of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 50

-Section 50

-Paragraph 4

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