Note 4 - Securities (Detail) (USD $)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Available-for-sale Securities, Gross Realized Gain (Loss)	$ 44,000	$ (37,000)	$ 4,000
Available-for-sale Securities	353,678,000	342,184,000
Held-to-maturity Securities Pledged as Collateral	45,645,000	46,784,000
Security One [Member] \| Available For Sale Securities [Member]
Available-for-sale Securities, Gross Realized Gain (Loss)			26,000
Security Two [Member] \| Carrying (Reported) Amount, Fair Value Disclosure [Member]
Available-for-sale Securities			0
Security Two [Member]
Other than Temporary Impairment Losses, Investments			150,000
Michigan Banks [Member]
Available-for-sale Securities	$ 500,000

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

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- Definition

The amount by which the fair value of an investment is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

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