XML 160 R38.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Adoption of Accounting Pronoucements (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2011
Adoption of Accounting Pronouncements [Abstract] |
Schedule Of New Accounting Pronouncements Balance Sheet Information |
Balance Sheet Information |  |  |  |  |  |  |
December 31, |  |  |  |  |  |  |
|  | 2011 |  | 2010
($ in thousands, except per share amounts) |  | As reported | As restated |  | As reported | As restated
Deferred policy acquisition costs | $ | 214,069 | 135,761 |  | 209,627 | 127,984
Total assets |  | 5,736,369 | 5,685,469 |  | 5,231,772 | 5,178,704
Stockholders' equity |  | 1,109,228 | 1,058,328 |  | 1,071,109 | 1,018,041
Book value per share |  | 20.39 | 19.45 |  | 19.95 | 18.97
Schedule Of New Accounting Pronouncements Income Statement Information |
Income Statement Information |  |  |  |  |  |  |  |
December 31, |  |  |  |  |  |  |  |
|  | 2011 |  | 2010 |  | 2009
($ in thousands, except per share amounts) |  | As reported | As restated |  | As reported | As restated |  | As reported | As restated
Underwriting (loss) profit | $ | (106,919) | (103,584) |  | (22,167) | (19,974) |  | 2,385 | 2,111
Net income |  | 19,865 | 22,033 |  | 65,541 | 66,966 |  | 36,398 | 36,220
Combined ratio |  | 107.4 | 107.2 | % | 101.6 | 101.4 |  | 99.8 | 99.9
Net income per share: |  |  |  |  |  |  |  |  |
Basic | $ | 0.37 | 0.41 |  | 1.23 | 1.26 |  | 0.69 | 0.69
Diluted |  | 0.36 | 0.40 |  | 1.20 | 1.23 |  | 0.68 | 0.68

X
- Definition Tabular disclosure of adoption of new accounting pronouncements, specifically the effects on certain Balance Sheet line items. + References No definition available. + Details
Name: | sigi_ScheduleOfNewAccountingPronouncementsBalanceSheetInformationTableTextBlock
Namespace Prefix: | sigi_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of adoption of new accounting pronouncements, specifically the effects on certain Income Statement line items. + References No definition available. + Details
Name: | sigi_ScheduleOfNewAccountingPronouncementsIncomeStatementInformationTableTextBlock
Namespace Prefix: | sigi_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

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