XML 43 R34.htm IDEA: XBRL DOCUMENT ﻿
v2.3.0.11

Investments (Available-For-Sale Securities Disclosure) (Details) (USD $) | Jun. 30, 2011 securities years | Dec. 31, 2010
--- | --- | ---
Cost/Amortized Cost | $ 2,570,766,000 |  | $ 2,344,027,000 |
Unrealized Gains | 99,860,000 |  | 83,786,000 |
Unrealized Losses | (8,812,000) |  | (15,435,000) |
Fair Value | 2,661,814,000 |  | 2,412,378,000 |
Number of held to maturity securities transferred to available-for-sale | 18 |  |  |
Securities reclassified from the HTM category to AFS carrying value | 46,600,000 |  |  |
Securities reclassified from the HTM category to AFS net unrecognized gain | 1,200,000 |  |  |
AFS Fixed Maturity Securities [Member] |  |  |  |
Cost/Amortized Cost | 2,442,579,000 |  | 2,285,988,000 |
Unrealized Gains | 89,807,000 |  | 72,189,000 |
Unrealized Losses | (7,149,000) |  | (15,435,000) |
Fair Value | 2,525,237,000 |  | 2,342,742,000 |
AFS Fixed Maturity Securities [Member] | U.S. Government and Government Agencies [Member] |  |  |  |
Cost/Amortized Cost | 288,760,000 |  | 312,384,000 |
Unrealized Gains | 8,223,000 |  | 8,292,000 |
Unrealized Losses | (52,000) |  | (147,000) |
Fair Value | 296,931,000 | [1] | 320,529,000 | [1]
Corporate securities fully guaranteed by the Federal Deposit Insurance Corporation ("FDIC") | 98,900,000 |  | 121,000,000 |
AFS Fixed Maturity Securities [Member] | Foreign Government [Member] |  |  |  |
Cost/Amortized Cost | 29,768,000 |  | 19,035,000 |
Unrealized Gains | 477,000 |  | 280,000 |
Unrealized Losses | (145,000) |  | (349,000) |
Fair Value | 30,100,000 |  | 18,966,000 |
AFS Fixed Maturity Securities [Member] | Obligations of States and Political Subdivisions [Member] |  |  |  |
Cost/Amortized Cost | 512,957,000 |  | 512,013,000 |
Unrealized Gains | 29,665,000 |  | 22,534,000 |
Unrealized Losses | (6,000) |  | (650,000) |
Fair Value | 542,616,000 |  | 533,897,000 |
AFS Fixed Maturity Securities [Member] | Corporate Securities [Member] |  |  |  |
Cost/Amortized Cost | 1,047,110,000 |  | 973,835,000 |
Unrealized Gains | 35,518,000 |  | 28,674,000 |
Unrealized Losses | (4,125,000) |  | (8,784,000) |
Fair Value | 1,078,503,000 |  | 993,725,000 |
AFS Fixed Maturity Securities [Member] | Asset-backed Securities ("ABS") [Member] |  |  |  |
Cost/Amortized Cost | 77,573,000 |  | 48,558,000 |
Unrealized Gains | 760,000 |  | 514,000 |
Unrealized Losses | (128,000) |  | (339,000) |
Fair Value | 78,205,000 |  | 48,733,000 |
AFS Fixed Maturity Securities [Member] | Commercial Mortgage-backed Securities ("CMBS") [Member] |  |  |  |
Cost/Amortized Cost | 105,706,000 |  | 103,374,000 |
Unrealized Gains | 4,599,000 |  | 4,024,000 |
Unrealized Losses | (1,181,000) |  | (2,923,000) |
Fair Value | 109,124,000 | [2] | 104,475,000 | [2]
Government guaranteed agency securities fair value | 72,300,000 |  | 71,900,000 |
AFS Fixed Maturity Securities [Member] | Residential Mortgage Backed Securities ("RMBS") [Member] |  |  |  |
Cost/Amortized Cost | 380,705,000 |  | 316,789,000 |
Unrealized Gains | 10,565,000 |  | 7,871,000 |
Unrealized Losses | (1,512,000) |  | (2,243,000) |
Fair Value | 389,758,000 | [3] | 322,417,000 | [3]
Government guaranteed agency securities fair value | 94,700,000 |  | 91,100,000 |
Equity Securities [Member] |  |  |  |
Cost/Amortized Cost | 128,187,000 |  | 58,039,000 |
Unrealized Gains | 10,053,000 |  | 11,597,000 |
Unrealized Losses | (1,663,000) |  | 0 |
Fair Value | $ 136,577,000 |  | $ 69,636,000 |
[1] | 1 U.S. government includes corporate securities fully guaranteed by the Federal Deposit Insurance Corporation ("FDIC") with a fair value of $98.9 million at June 30, 2011 and $121.0 million at December 31, 2010.
[2] | 2 CMBS includes government guaranteed agency securities with a fair value of $72.3 million at June 30, 2011 and $71.9 million at December 31, 2010.
[3] | 3 RMBS includes government guaranteed agency securities with a fair value of $94.7 million at June 30, 2011 and $91.1 million at December 31, 2010.

X
- Definition This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities. + Details
Name: | sigi_AvailableForSaleSecuritiesGrossUnrealizedGain
Namespace Prefix: | sigi
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition This item represents the gross unrealized losses for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities. + Details
Name: | sigi_AvailableForSaleSecuritiesGrossUnrealizedLosses1
Namespace Prefix: | sigi
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Represents the fair value of corporate securities fully guaranteed by the Federal Deposit Insurance Corporation. + Details
Name: | sigi_CorporateSecuritiesFullyGuaranteedByFederalDepositInsuranceCorporation
Namespace Prefix: | sigi
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The fair value of agency securities that are issued by a particular agency of the federal government which are guaranteed by the U.S. government. + Details
Name: | sigi_GovernmentGuaranteedAgencySecuritiesFairValue
Namespace Prefix: | sigi
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the unrealized gain or loss recognized in other comprehensive income (a separate component of shareholders' equity) as a result of securities categorized as held-to-maturity being transferred to the available-for-sale securities category. + Details
Name: | sigi_HeldToMaturitySecuritiesReclassifiedToAvailableForSaleSecuritiesUnrecognizedGainLoss
Namespace Prefix: | sigi
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition This item represents the number of held-to-maturity securities reclassified to available-for-sale securities due to an unanticipated significant deterioration in credit quality. + Details
Name: | sigi_NumberOfHeldToMaturitySecuritiesTransferredSecurityAtCarryingValue
Namespace Prefix: | sigi
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition For an unclassified balance sheet, this item represents investments in debt and equity securities which are categorized neither as held-to-maturity nor trading. Such securities are reported at fair value, with unrealized gains and losses excluded from earnings and reported in a separate component of shareholders' equity (other comprehensive income), unless the Available-for-sale Security is designated as a hedge or is determined to have had an other than temporary decline in fair value below its amortized cost basis. All or a portion of the unrealized holding gain or loss of an Available-for-sale Security that is designated as being hedged in a fair value hedge shall be recognized in earnings during the period of the hedge, as should other than temporary declines in fair value below costs basis. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 16 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 22 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 12 -Subparagraph b Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 13 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 14 + Details
Name: | us-gaap_AvailableForSaleSecurities
Namespace Prefix: | us-gaap
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments made for accretion, amortization, other-than-temporary impairments, and hedging, if any. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 7 -Footnote 2 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 19 + Details
Name: | us-gaap_AvailableForSaleSecuritiesAmortizedCost
Namespace Prefix: | us-gaap
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition For any transfer of securities categorized as held-to-maturity, this item represents the net carrying amount of the transferred security to another category of investments in debt and equity securities (trading or available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 22 + Details
Name: | us-gaap_HeldToMaturitySecuritiesTransferredSecurityAtCarryingValue
Namespace Prefix: | us-gaap
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant