XML 52 R28.htm IDEA: XBRL DOCUMENT
v2.3.0.15

Reinsurance (Tables) | 9 Months Ended
--- | ---
Sep. 30, 2011
Reinsurance [Abstract] |
List of Direct, Assumed, and Ceded Reinsurance Amounts |
|  | Quarter ended |  | Nine Months ended
|  | September 30, |  | September 30,
($ in thousands) |  | 2011 |  | 2010 |  |  | 2011 |  | 2010
Premiums written: |  |  |  |  |  |  |  |  |
Direct | $ | 453,768 |  | 431,312 |  |  | 1,324,705 |  | 1,274,061
Assumed |  | 22,575 |  | 15,372 |  |  | 29,765 |  | 21,561
Ceded |  | (79,511) |  | (79,570) |  |  | (221,300) |  | (206,893)
Net | $ | 396,832 |  | 367,114 |  |  | 1,133,170 |  | 1,088,729
Premiums earned: |  |  |  |  |  |  |  |  |
Direct | $ | 425,231 |  | 413,759 |  |  | 1,257,087 |  | 1,238,912
Assumed |  | 7,626 |  | 9,158 |  |  | 18,866 |  | 20,858
Ceded |  | (73,894) |  | (68,208) |  |  | (210,067) |  | (196,669)
Net | $ | 358,963 |  | 354,709 |  |  | 1,065,886 |  | 1,063,101
Losses and loss expenses incurred: |  |  |  |  |  |  |  |  |
Direct | $ | 638,219 |  | 277,111 |  |  | 1,204,586 |  | 834,431
Assumed |  | 5,977 |  | 6,612 |  |  | 13,549 |  | 11,535
Ceded |  | (338,238) |  | (38,704) |  |  | (388,416) |  | (106,824)
Net | $ | 305,958 |  | 245,019 |  |  | 829,719 |  | 739,142
Ceded Premiums and Losses Related to Flood Operations |
National Flood Insurance Program |  | Quarter ended |  | Nine Months ended
|  | September 30, |  | September 30,
($ in thousands) |  | 2011 |  | 2010 |  |  | 2011 |  | 2010
Ceded premiums written | $ | (55,198) |  | (57,838) |  |  | (158,777) |  | (148,296)
Ceded premiums earned |  | (50,256) |  | (47,240) |  |  | (147,111) |  | (137,220)
Ceded losses and loss expenses incurred |  | (301,725) |  | (11,227) |  |  | (331,604) |  | (54,303)

X
- Definition Schedule of the company's direct, assumed and ceded reinsurance amounts by premiums written, premiums earned, and losses and loss expenses incurred. + Details
Name: | sigi_ScheduleOfDirectAssumedAndCededReinsuranceAmountsTextBlock
Namespace Prefix: | sigi
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition This table discloses the premiums and losses and loss expenses that are ceded to the National Flood Insurance Program. + Details
Name: | sigi_ScheduleOfFloodCededPremiumsAndLossesTextBlock
Namespace Prefix: | sigi
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

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