XML 74 R38.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Investments (Investments Pledged as Collateral) (Details) (USD $) In Millions, unless otherwise specified | Jun. 30, 2014
--- | ---
Schedule of Available-for-sale Securities [Line Items] |
Fixed Income Securities PledgedFor FHLBI Collateral | $ 61.6
Securities Pledged As Collateral For Reinsurance Obligations | 16.4
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies | 26.0
Securities Pledged As Collateral | 104.0
Outstanding Borrowing With The Federal Home Loan Bank Of Indianapolis | 58
U.S. Government and Government Agencies [Member] |
Schedule of Available-for-sale Securities [Line Items] |
Fixed Income Securities PledgedFor FHLBI Collateral | 22.9
Securities Pledged As Collateral For Reinsurance Obligations | 0
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies | 26.0
Securities Pledged As Collateral | 48.9
Obligations of States and Political Subdivisions [Member] |
Schedule of Available-for-sale Securities [Line Items] |
Fixed Income Securities PledgedFor FHLBI Collateral | 0
Securities Pledged As Collateral For Reinsurance Obligations | 5.7
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies | 0
Securities Pledged As Collateral | 5.7
Corporate Securities [Member] |
Schedule of Available-for-sale Securities [Line Items] |
Fixed Income Securities PledgedFor FHLBI Collateral | 0
Securities Pledged As Collateral For Reinsurance Obligations | 5.3
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies | 0
Securities Pledged As Collateral | 5.3
Asset-Backed Securities [Member] |
Schedule of Available-for-sale Securities [Line Items] |
Fixed Income Securities PledgedFor FHLBI Collateral | 0
Securities Pledged As Collateral For Reinsurance Obligations | 2.0
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies | 0
Securities Pledged As Collateral | 2.0
Commercial Mortgage Backed Securities [Member] |
Schedule of Available-for-sale Securities [Line Items] |
Fixed Income Securities PledgedFor FHLBI Collateral | 1.9
Securities Pledged As Collateral For Reinsurance Obligations | 0
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies | 0
Securities Pledged As Collateral | 1.9
Residential Mortgage Backed Securities [Member] |
Schedule of Available-for-sale Securities [Line Items] |
Fixed Income Securities PledgedFor FHLBI Collateral | 36.8
Securities Pledged As Collateral For Reinsurance Obligations | 3.2
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies | 0
Securities Pledged As Collateral | 40.0
Fixed Income Securities [Member] |
Schedule of Available-for-sale Securities [Line Items] |
Fixed Income Securities PledgedFor FHLBI Collateral | 61.6
Securities Pledged As Collateral For Reinsurance Obligations | 16.2
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies | 26.0
Securities Pledged As Collateral | 103.8
Short-Term Investments [Member] |
Schedule of Available-for-sale Securities [Line Items] |
Fixed Income Securities PledgedFor FHLBI Collateral | 0
Securities Pledged As Collateral For Reinsurance Obligations | 0.2
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies | 0
Securities Pledged As Collateral | $ 0.2

X
- Definition This item represents the carrying value of debt securities, both held-to-maturity securities and available-for-sale securities, that are on deposit with various state and regulatory agencies to comply with insurance laws. + References No definition available. + Details
Name: | sigi_CarryingValueBondsOnDepositWithVariousStateandRegulatoryAgencies
Namespace Prefix: | sigi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Total value amount of investments pledged as collateral + References No definition available. + Details
Name: | sigi_SecuritiesPledgedAsCollateral
Namespace Prefix: | sigi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The carrying value of investments pledged as collateral for reinsurance obligations + References No definition available. + Details
Name: | sigi_SecuritiesPledgedAsCollateralForReinsuranceObligations
Namespace Prefix: | sigi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of the collateral pledged in support of federal home loan bank advances outstanding. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 50 -Paragraph 3 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823 + Details
Name: | us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Including both current and noncurrent portions, Federal Home Loan Bank borrowings initially due beyond one year or beyond the normal operating cycle if longer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 16 -Article 9 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64702-112823 + Details
Name: | us-gaap_FederalHomeLoanBankAdvancesLongTerm
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration