Derivative Instruments (Fair Value of Hedged Interest Rate Swaps) (Details) (Interest Rate Swap [Member], Available-for-sale Securities [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2011
Interest Rate Swap [Member] \| Available-for-sale Securities [Member]
Net Derivatives Gains Losses Recognized On Fair Value Derivatives And Related Hedged Items [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Net	$ (785)
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	1,402
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net	$ 617

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Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 25

-Section 50

-Paragraph 1

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986

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Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4A

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5618551-113959

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4C

-Subparagraph (a),(c),(d),(e)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624171-113959

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Amount of gain (loss)recognized in the income statement from the hedging ineffectiveness of a fair value hedge.

+ References

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