Derivatives and Hedging Activities Derivatives and Hedging Activities (Details Textual) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Interest rate swap derivative financial instruments
Investment securities pledged as collateral	$ 1,673,263,000	$ 1,635,316,000
Interest Rate Swap
Interest rate swap derivative financial instruments
Investment securities pledged as collateral	20,339,000
Collateral pledged from counterparties to the Company	0
Interest Rate Swap One
Interest rate swap derivative financial instruments
Forecasted Notional Amount	160,000,000
Interest rate expense recorded on interest rate swap	1,066,000
Unrealized loss to be reclassified within twelve months	$ 5,064,000

The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (c)

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The premium (cost) of a hedge, expensed during the period.

+ References

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- Definition

Nominal or face amount used to calculate payments on the derivative liability.

+ References

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

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-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

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The carrying value as of the balance sheet date of the assets received as collateral against securities loaned to other broker-dealers. Borrowers of securities generally are required to provide collateral to the lenders of securities, commonly cash but sometimes other securities or standby letters of credit, with a value slightly higher than that of the securities borrowed. In instances where the entity is permitted to sell or re-pledge these securities, the entity reports the fair value of the collateral received and the related obligation to return the collateral as a liability.

+ References

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-Name Accounting Standards Codification

-Topic 860

-SubTopic 30

-Section 50

-Paragraph 1A

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Fair value of financial instrument held by the entity for its own account (proprietary securities) for trading or investment purposes that are carried at fair value and pledged to counterparties as collateral for financing transactions.

+ References

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