Derivative Financial Instruments - Gross/Net (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Derivative assets
Net asset (liability)	$ 818	$ 85,126
Derivative liabilities
Net asset (liability)	1,457	(67,654)
Derivative Financial Instruments, Assets [Member]
Derivative assets
Gross amounts of recognized assets presented in the consolidated balance sheets	818	87,531
Derivatives subject to enforceable master netting arrangement	0	(2,880)
Cash collateral pledged	0	475
Derivative Financial Instruments, Liabilities [Member]
Derivative liabilities
Gross amounts of recognized liabilities presented in the consolidated balance sheets	(7,063)	(77,826)
Derivatives subject to enforceable master netting arrangement	0	2,880
Cash collateral pledged	$ 8,520	$ 7,292

Derivative Assets Not Designated As Hedging Instruments, Net

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- Definition

Derivative Liabilities Not Designated As Hedging Instruments, Net

+ References

No definition available.

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Fair value, before 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 elected not to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)
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Fair value of liability associated with 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, and obligation to return cash collateral under master netting arrangements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
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- References

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Amount of obligation to return cash collateral under master netting arrangements that have not been offset against derivative assets.

+ References

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Amount of right to receive cash collateral under master netting arrangements that have not been offset against derivative liabilities.

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Fair value of asset associated with 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, and right to receive cash collateral under master netting arrangements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Fair value, before 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 elected not to be offset.

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