Securities (Details Textual) (USD $)	9 Months Ended
Sep. 30, 2013 Institutions Tranche	Sep. 30, 2012	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Carrying value of securities held to maturity	$ 4,292,000
Net gain recognized on sale of securities held to maturity	169,000
Securities classified as held to maturity		0
Investments in pooled trust preferred securities, cost basis	475,814,000		357,633,000
Securities available for sale, at fair value	464,733,000		356,311,000
Number of institutions issuing debt (institutions)	330
Number of securities representing interests in tranches of trusts (tranches)	4
Secure government, public and trust deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities pledged as collateral	581,266,000		308,362,000
Short-term borrowings [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities pledged as collateral	$ 5,684,000		$ 19,006,000

Held to maturities securities sold.

No definition available.

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- Definition

Number of institutions issuing debt.

+ References

No definition available.

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Number of securities representing interests in tranches of trusts.

+ References

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

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- Definition

This item represents the cost of debt and equity 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.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.2)

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- Definition

The fair value of available-for-sale securities that serve as collateral for borrowings.

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-Topic 310

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- Definition

For any sales of securities categorized as held-to-maturity, this item represents the net carrying amount of the sold security.

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- Definition

This item represents the gain (loss) realized on the sale of held-to-maturity securities disposed of during the period. Additionally, this item may include, if not separately presented, any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt securities which are being or have been recognized in earnings during the period.

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