Schedule of Volume of Activity Futures Contracts (Details) (Eurodollar Future)	12 Months Ended
Dec. 31, 2013 Contract
Eurodollar Future
Derivatives Fair Value [Line Items]
Number of contracts, Beginning balance
Purchases	125,860
Settlements	(28,164)
Maturities	(2,369)
Number of contracts, Ending balance	95,327

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

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 1B

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 1A

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5579245-113959

Name:	us-gaap_DerivativeNumberOfInstrumentsHeld
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant