Derivative Financial Instruments (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010
Derivative [Line Items]
Aggregate notional amount designated as cash flow hedges	$ 715,104
Fair value of derivatives in net liability position with credit-risk-related contingent features	57,182
Cash collateral posted with derivative counterparties	68,190
Number of derivative instruments held	8
Interest Expense [Member] \| Cash Flow Hedges [Member]
Derivative [Line Items]
Estimated amount to be reclassified	17,390
Interest Rate Swaps [Member] \| Variable Interest Entities [Member]
Derivative [Line Items]
Aggregate notional amount designated as cash flow hedges	40,104
Fair value of cash flow hedges	40
Interest Rate Swaps [Member] \| Not Designated As Hedges [Member]
Derivative [Line Items]
Number of derivative instruments held	92
Not Designated As Hedges [Member]
Derivative [Line Items]
Aggregate notional amount derivatives	597,294
Net gains (losses) related to changes in fair value of derivatives	$ 122	$ 71

Net fair value of all derivative instruments designated as cash flow hedging instruments, which is ordinarily reflected within other comprehensive income.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 107

-Paragraph 10

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

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The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features.

+ References

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-Name Accounting Standards Codification

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The estimated value of gains (losses), net anticipated to be transferred in the future from accumulated other comprehensive income into earnings.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The aggregate fair value amounts of derivative instruments that contain credit-risk-related contingent features that are in a net liability position at the end of the reporting period. For nonderivative instruments that are designated and qualify as hedging instruments, the fair value amounts are the carrying value of the nonderivative hedging instrument, including the adjustment for the foreign currency transaction gain (loss) on that instrument.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

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The number of derivative instruments of a particular group held by the entity.

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Amount of gain (loss) included in earnings for the period from the increase (decrease) in fair value of interest rate derivatives not designated as hedging instruments.

+ References

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

-Publisher FASB

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-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.

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Aggregate notional amount of all interest rate derivatives designated as hedging instruments in cash flow hedges. Notional amount refers to the monetary amount specified in the interest rate derivative contract.

+ References

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-Glossary Notional Amount

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Aggregate notional amount of all derivatives not designated as a hedging instrument. The notional amount relates to a number of currency units, shares, bushels, pounds, or other units specified in a derivative instrument.

+ References

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