Derivatives and Hedging Activity - Effect on Financial Statements (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Derivatives
Gain (loss) on derivative financial instruments, net	$ (24,224)	$ (2,328)	$ (66,159)	$ (6,793)
Derivatives not designated as hedging instruments
Derivatives
Gain (loss) on derivative financial instruments, net	(24,224)	(2,328)	(66,159)	(6,793)
Interest rate swaps \| Derivatives not designated as hedging instruments
Derivatives
Gain (loss) on derivative financial instruments, net	(3,836)	(626)	(10,190)	(25,899)
Foreign exchange contracts \| Derivatives not designated as hedging instruments
Derivatives
Gain (loss) on derivative financial instruments, net	(19,650)	(189)	(54,814)	21,160
Credit index instruments \| Derivatives not designated as hedging instruments
Derivatives
Gain (loss) on derivative financial instruments, net	(738)	(1,513)	(1,155)	(2,054)
Cash flow hedges \| Interest rate swaps \| Derivatives designated as hedging instruments
Derivatives
Gain (Loss) Recognized in OCI (effective portion)	(3)	107	45	(397)
Gain (Loss) Reclassified from AOCI into Income (effective portion)	$ 19	$ (78)	$ (11)	$ (261)

The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4D
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624177-113959

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- Definition

The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.

+ References

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Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects.

+ 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=84234895&loc=SL5618551-113959

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