Repurchase Agreements Repurchase Agreements (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase, Fair Value of Collateral	$ 386,800,000	$ 418,300,000
Securities Sold under Agreements to Repurchase	365,283,000	324,425,000
Securities Sold under Agreements to Repurchase, Gross	365,283,000	324,425,000
Government Agency
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase	6,909,000	6,914,000
U. S. Treasury
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase	358,374,000	186,010,000
Mortgage Backed Securities, Other [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase		131,501,000
Overnight and continuous
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase	335,283,000	294,425,000
Overnight and continuous \| Government Agency
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase	0	0
Overnight and continuous \| U. S. Treasury
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase	335,283,000	162,924,000
Overnight and continuous \| Mortgage Backed Securities, Other [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase		131,501,000
Up to 30 days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase	0	0
Up to 30 days \| Government Agency
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase	0	0
Up to 30 days \| U. S. Treasury
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase	0	0
Up to 30 days \| Mortgage Backed Securities, Other [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase		0
30 - 90 days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase	0	0
30 - 90 days \| Government Agency
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase	0	0
30 - 90 days \| U. S. Treasury
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase	0	0
30 - 90 days \| Mortgage Backed Securities, Other [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase		0
Greater than 90 days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase	30,000,000	30,000,000
Greater than 90 days \| Government Agency
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase	6,909,000	6,914,000
Greater than 90 days \| U. S. Treasury
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase	23,091,000	23,086,000
Greater than 90 days \| Mortgage Backed Securities, Other [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase		$ 0

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Amount, after the 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 not subject to a master netting arrangement and not elected to be offset.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.13(1))

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-Section 50

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

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-Article 9

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- Definition

Fair value of securities pledged as collateral against securities sold under agreement to repurchase.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

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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.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=34720828&loc=SL20225862-175312

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