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Derivative Instruments and Hedging Activities Schedule of Interest Rate Swap Receivers Associated with the Investment Portfolio (Details) (USD $)
In Thousands, unless otherwise specified |
Sep. 30, 2014
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Jun. 30, 2014
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Dec. 31, 2013
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Sep. 30, 2013
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Jun. 30, 2013
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Dec. 31, 2012
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|---|---|---|---|---|---|---|
| Derivative [Line Items] | ||||||
| Derivative, Notional Amount | $ 57,015,981 | $ 43,379,217 | $ 37,366,610 | $ 36,472,401 | $ 44,262,605 | $ 22,377,656 |
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Interest Rate Swap [Member]
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| Derivative [Line Items] | ||||||
| Derivative, Notional Amount | 27,770,655 | 23,628,148 | 19,619,000 | 17,575,000 | 18,485,000 | 14,070,000 |
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Interest Rate Risk Associated with the Investment Portfolio [Member] | Interest Rate Swap [Member] | Short [Member]
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| Derivative [Line Items] | ||||||
| Derivative, Notional Amount | 3,276,477 | 2,154,000 | ||||
| Derivative, Average Variable Interest Rate | 2.521% | 2.337% | ||||
| Derivative, Average Fixed Interest Rate | 0.235% | 0.24% | ||||
| Derivative, Average Remaining Period Until Maturity | 8.62 | 7.84 | ||||
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Interest Rate Risk Associated with the Investment Portfolio [Member] | Derivative Maturity Over Three And Within Four Years From Balance Sheet Date [Member] | Interest Rate Swap [Member] | Short [Member]
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| Derivative [Line Items] | ||||||
| Derivative, Notional Amount | 575,000 | |||||
| Derivative, Average Variable Interest Rate | 1.44% | |||||
| Derivative, Average Fixed Interest Rate | 0.234% | |||||
| Derivative, Average Remaining Period Until Maturity | 4.14 | |||||
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Interest Rate Risk Associated with the Investment Portfolio [Member] | Derivative Maturity Over Four Years From Balance Sheet Date [Member] | Interest Rate Swap [Member] | Short [Member]
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| Derivative [Line Items] | ||||||
| Derivative, Notional Amount | $ 2,701,477 | $ 2,154,000 | ||||
| Derivative, Average Variable Interest Rate | 2.751% | 2.337% | ||||
| Derivative, Average Fixed Interest Rate | 0.235% | 0.24% | ||||
| Derivative, Average Remaining Period Until Maturity | 9.57 | 7.84 |