Securities (Details Textual) (USD $)	Sep. 30, 2012	Dec. 31, 2011
Securities (Textual) [Abstract]
Fair value of debt securities with unrealized losses	$ 8,905,000	$ 19,291,000
Aggregate depreciation of securities with unrealized losses	79,000	59,000
Available for sale securities	135,660,000	172,992,000
Aggregate appreciation as a percentage of total amortized cost of securities	3.80%
Securities (Additional Textual) [Abstract]
Fair Value of Debt and Equity Securities with Unrealized Gains	106,500,000
Aggregate appreciation of securities with unrealized gains	4,996,000	5,893,000
Total securities of specific issuer, other than U.S. Government and its agencies, maximum percentage of stockholders' equity	10.00%
Debt securities [Member]
Securities (Textual) [Abstract]
Number of debt securities with unrealized losses	6
Fair value of debt securities with unrealized losses	8,900,000
Aggregate depreciation of securities with unrealized losses	100,000
Number of debt securities with unrealized gains	204
Aggregate depreciation as a percentage of total amortized cost of securities	0.06%
State of Michigan and all its political subdivisions [Member]
Securities (Textual) [Abstract]
Available for sale securities	27,000,000	31,700,000
Amortized cost of securities	25,700,000	30,500,000
Mutual funds [Member]
Securities (Textual) [Abstract]
Fair value of debt securities with unrealized losses	0	0
Aggregate depreciation of securities with unrealized losses	0	0
Available for sale securities	1,406,000	1,354,000
Securities (Additional Textual) [Abstract]
Aggregate appreciation of securities with unrealized gains	68,000	42,000
U.S. Government agency debt obligations and mortgage-backed securities [Member]
Securities (Textual) [Abstract]
Carrying value of securities pledged to secure repurchase agreements and letters of credit issued	$ 74,800,000	$ 109,000,000

Available for sale securities, aggregate appreciation, percentage of amortized cost of securities.

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Available for sale securities, aggregate depreciation, percentage of amortized cost of securities.

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Available for sale securities fair value with unrealized gains.

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Number of debt securities with unrealized gains.

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Number of debt securities with unrealized losses.

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Securities of specific issuer other than U.S. Government and its agencies, maximum percentage of stockholders' equity.

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This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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Amount of the excess of amortized cost basis over fair value of securities in a loss position and categorized neither as held-to-maturity nor trading securities.

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This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities.

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This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

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This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

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The carrying amount of securities categorized neither as held-to-maturity nor trading which serve as security for borrowings or other arrangements.

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