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Reinsurance (Tables) | 6 Months Ended
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Jun. 30, 2012
Reinsurance Disclosures [Abstract] |
List Of Direct, Assumed, And Ceded Reinsurance Amounts [Text Block] |
|  | Quarter ended June 30, |  | Six Months ended June 30,
($ in thousands) |  | 2012 |  | 2011 |  | 2012 |  | 2011
Premiums written: |  |  |  |  |  |  |  |  |  |  |  |
Direct |  | $ | 507,520 |  |  | 447,595 |  |  | 983,486 |  |  | 870,937 |
Assumed |  | 4,747 |  |  | 1,537 |  |  | 26,736 |  |  | 7,190 |
Ceded |  | (86,704 | ) |  | (74,629 | ) |  | (164,487 | ) |  | (141,789 | )
Net |  | $ | 425,563 |  |  | 374,503 |  |  | 845,735 |  |  | 736,338 |
Premiums earned: |  |  |  |  |  |  |  |  |  |  |  |
Direct |  | $ | 463,330 |  |  | 418,977 |  |  | 915,318 |  |  | 831,856 |
Assumed |  | 16,039 |  |  | 5,351 |  |  | 31,088 |  |  | 11,240 |
Ceded |  | (87,157 | ) |  | (68,748 | ) |  | (175,365 | ) |  | (136,173 | )
Net |  | $ | 392,212 |  |  | 355,580 |  |  | 771,041 |  |  | 706,923 |
Losses and loss expenses incurred: |  |  |  |  |  |  |  |  |  |  |  |
Direct |  | $ | 301,451 |  |  | 296,963 |  |  | 553,654 |  |  | 566,367 |
Assumed |  | 10,470 |  |  | 3,739 |  |  | 21,069 |  |  | 7,572 |
Ceded |  | (24,018 | ) |  | (26,147 | ) |  | (33,914 | ) |  | (50,178 | )
Net |  | $ | 287,903 |  |  | 274,555 |  |  | 540,809 |  |  | 523,761 |
Ceded Premiums and Losses Related to Flood Operations | s:
National Flood Insurance Program |  | Quarter ended June 30, |  | Six Months ended June 30,
($ in thousands) |  | 2012 |  | 2011 |  | 2012 |  | 2011
Ceded premiums written |  | $ | (60,525 | ) |  | (55,265 | ) |  | (112,249 | ) |  | (103,579 | )
Ceded premiums earned |  | (52,768 | ) |  | (48,907 | ) |  | (104,673 | ) |  | (96,855 | )
Ceded losses and loss expenses incurred |  | $ | (6,754 | ) |  | (15,339 | ) |  | 8,168 |  |  | (29,879 | )

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- Definition Schedule of the company's direct, assumed and ceded reinsurance amounts by premiums written, premiums earned, and losses and loss expenses incurred. + References No definition available. + Details
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- Definition This table discloses the premiums and losses and loss expenses that are ceded to the National Flood Insurance Program. + References No definition available. + Details
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Namespace Prefix: | sigi_
Data Type: | nonnum:textBlockItemType
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- Details
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Namespace Prefix: | us-gaap_
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