Counterparty Risk (% Of Due from Brokers) (Details)	Sep. 30, 2016
Morgan Stanley [Member]
Concentration Risk [Line Items]
% of Total Due from Brokers	38.00%
J.P. Morgan Securities Inc [Member]
Concentration Risk [Line Items]
% of Total Due from Brokers	17.00%

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_ConcentrationRiskLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration