Counterparty Risk (% Of Total Collateral On Reverse Repurchase Agreements) (Details)	Jun. 30, 2013
Deutsche Bank [Member]
Concentration Risk [Line Items]
% of Total Collateral on Reverse Repurchase Agreements	18.00%
Guggenheim Capital Markets [Member]
Concentration Risk [Line Items]
% of Total Collateral on Reverse Repurchase Agreements	18.00%
Royal Bank Of Canada [Member]
Concentration Risk [Line Items]
% of Total Collateral on Reverse Repurchase Agreements	15.00%