XML 132 R102.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Retirement Plans (Deferred Compensation Plan) (Details) (USD $) In Millions, unless otherwise specified | 12 Months Ended
--- | ---
Dec. 31, 2013 | Dec. 31, 2011
Maximum Employee Contribution Of Annual Salary To Deferred Compensation Plan Percentage | 50.00% |
Maximum Employee Contribution Of Annual Bonus To Deferred Compensation Plan Percentage | 100.00% |
Deferred Compensation Plan Contributions By Employer | $ 0.2 | $ 0.1

X
- Definition Maximum percentage of defined compensation, related to annual bonus, that an employee can contribute to the nonqualified deferred compensation plan. + References No definition available. + Details
Name: | sigi_MaximumEmployeeContributionOfAnnualBonusToDeferredCompensationPlanPercentage
Namespace Prefix: | sigi_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Maximum percentage of defined compensation, related to annual base salary, that an employee can contribute to the nonqualified deferred compensation plan. + References No definition available. + Details
Name: | sigi_MaximumEmployeeContributionOfAnnualSalaryToDeferredCompensationPlanPercentage
Namespace Prefix: | sigi_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The amount of payment into the fund established for purposes of making future disbursements to the individual in accordance with the terms and understanding of the deferred compensation arrangement. + References No definition available. + Details
Name: | us-gaap_DeferredCompensationArrangementWithIndividualEmployerContribution
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration