XML 41 R32.htm IDEA: XBRL DOCUMENT  v2.3.0.11

Statements of Cash Flow (Cash Flow Supplemental Disclosures) (Details) (USD $) In Thousands	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
Statements of Cash Flow [Abstract]
Interest	$ 9,103	$ 9,649
Federal income tax	$ 3,673	$ 14,000

X

- Definition

The amount of cash paid during the current period to federal authorities as taxes on income, net of any cash received during the current period as refunds for the overpayment of federal taxes.

+ Details

Name:	sigi_FederalIncomeTaxesPaidNet
Namespace Prefix:	sigi
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

The amount of cash paid during the current period for interest owed on money borrowed; includes amount of interest capitalized

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 29

+ Details

Name:	us-gaap_InterestPaid
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Details

Name:	us-gaap_StatementOfCashFlowsAbstract
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration