Derivatives and Balance Sheet Offsetting Balance Sheet Offsetting (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Balance Sheet Offsetting [Line Items]
Repurchase agreements, amounts offset in balance sheet	$ 0	$ 0
Repurchase agreements, net amount presented in statement of financial position	96,852	105,080
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Securities	(96,852)	(105,080)
Securities sold under agreements to repurchase, amount not offset	0	0
Interest Rate Contracts [Member]
Balance Sheet Offsetting [Line Items]
Derivative Assets, Gross Amounts Offset in the Balance Sheets	0	0
Derivative Asset	14,244	11,800
Derivative, Collateral, Obligation to Return Securities	0	0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	14,244	11,800
Derivative Liability, Gross Amounts Offset in Balance Sheets	0	0
Derivative Liability	14,300	11,851
Derivative, Collateral, Right to Reclaim Securities	(14,300)	(11,851)
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	0	0
Not Designated as Hedging Instrument [Member] \| Interest Rate Contracts [Member] \| Other Assets [Member]
Balance Sheet Offsetting [Line Items]
Fair value of asset derivative instruments	14,244	11,800
Not Designated as Hedging Instrument [Member] \| Interest Rate Contracts [Member] \| Other Liabilities [Member]
Balance Sheet Offsetting [Line Items]
Fair value of liability derivative instruments	14,300	11,851
Available-for-sale Securities [Member]
Balance Sheet Offsetting [Line Items]
Securities Sold under Agreements to Repurchase, Gross	$ 96,852	$ 105,080

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Amount of right to receive securities collateral under master netting arrangements that have not been offset against securities sold under agreement to repurchase.

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Amount, before effects of master netting arrangements, of funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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