Derivatives and Hedging Activities (Details) (Derivatives Not Designated as Hedging Instruments [Member], Interest Rate Contracts [Member], USD $)	Dec. 31, 2012	Dec. 31, 2011
Derivative [Line Items]
Notional Amount of Interest Rate Derivative Instruments Not Designated as Hedging Instruments	$ 177,000,000	$ 160,300,000
Other Assets [Member]
Derivative [Line Items]
Fair value of asset derivative instruments	14,921,000	16,302,000
Other Liabilities [Member]
Derivative [Line Items]
Fair value of liability derivative instruments	$ 14,921,000	$ 16,302,000

No authoritative reference available.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 205G

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 44C

-Subparagraph a

-Clause 1

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4B

-Subparagraph (a),(c)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624163-113959

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant