Derivative Instruments and Hedging Activities Credit Risk - Counterparty Exposure (Details) - USD ($) $ in Thousands |
Dec. 31, 2017 |
Dec. 31, 2016 |
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| Offsetting Assets and Liabilities [Line Items] | ||
| Derivative assets, at fair value | $ 309,918 | $ 324,182 |
| Derivative liabilities, at fair value | $ 31,903 | $ 12,501 |
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- Definition [Line Items] for Disclosure of information about derivative and financial assets and liabilties that are subject to offsetting, including enforceable master netting arrangements. No definition available.
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- Definition Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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