Investments (Securities Pledged as Collateral Related to Repurchase Reverse Repurchase Program) (Details) $ in Thousands	Jun. 30, 2015 USD ($)
Assets Sold under Agreements to Repurchase [Line Items]
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	$ 313,771
Securities Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	340,201
SecuredBorrowingsGrossDifferenceAmount	26,430
US Treasury Securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	200,531
Residential Mortgage Backed Securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	104,144
Other Debt Obligations [Member]
Assets Sold under Agreements to Repurchase [Line Items]
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	9,096
Maturity Overnight [Member]
Assets Sold under Agreements to Repurchase [Line Items]
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	9,096
Maturity Overnight [Member] | US Treasury Securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	0
Maturity Overnight [Member] | Residential Mortgage Backed Securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	0
Maturity Overnight [Member] | Other Debt Obligations [Member]
Assets Sold under Agreements to Repurchase [Line Items]
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	9,096
Maturity up to 30 days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	0
Maturity up to 30 days [Member] | US Treasury Securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	0
Maturity up to 30 days [Member] | Residential Mortgage Backed Securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	0
Maturity up to 30 days [Member] | Other Debt Obligations [Member]
Assets Sold under Agreements to Repurchase [Line Items]
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	0
Maturity 30 to 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	23,237
Maturity 30 to 90 Days [Member] | US Treasury Securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	23,237
Maturity 30 to 90 Days [Member] | Residential Mortgage Backed Securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	0
Maturity 30 to 90 Days [Member] | Other Debt Obligations [Member]
Assets Sold under Agreements to Repurchase [Line Items]
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	0
Maturity over 90 days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	281,438
Maturity over 90 days [Member] | US Treasury Securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	177,294
Maturity over 90 days [Member] | Residential Mortgage Backed Securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	104,144
Maturity over 90 days [Member] | Other Debt Obligations [Member]
Assets Sold under Agreements to Repurchase [Line Items]
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	$ 0