XML 82 R70.htm IDEA: XBRL DOCUMENT
v3.19.2

Leases (Maturities of Lease Liabilities) (Details) - USD ($) $ in Thousands | Jun. 30, 2019 | Jan. 01, 2019 | Dec. 31, 2018
--- | --- | --- | ---
Lease Liabilities Payments Due [Line Items] |  |  |  |  |
Finance lease liability, due remainder of fiscal year | $ 389 |  |  |  |
Finance lease liability, due 2020 | 448 |  |  |  |
Finance lease liability, due 2021 | 244 |  |  |  |
Finance lease liability, due 2022 | 53 |  |  |  |
Finance lease liability, due 2023 | 0 |  |  |  |
Finance lease liability, due after 2023 | 0 |  |  |  |
Finance lease liability, total payments | 1,134 |  |  |  |
Finance lease imputed interest | 25 |  |  |  |
Finance lease liabilities | 1,109 | [1] | $ 900 | $ 0 | [1]
Operating lease liability, due remainder of fiscal year | 4,044 |  |  |  |
Operating lease liability, due 2020 | 7,737 |  |  |  |
Operating lease liability, due 2021 | 5,483 |  |  |  |
Operating lease liability, due 2022 | 3,912 |  |  |  |
Operating lease liability, due 2023 | 2,900 |  |  |  |
Operating lease liability, due after 2023 | 9,698 |  |  |  |
Operating lease liability, total payments | 33,774 |  |  |  |
Operating lease imputed interest | 3,438 |  |  |  |
Operating lease liability | 30,336 |  | $ 21,000 |  |
Total lease liability, due remainder of fiscal year | 4,433 |  |  |  |
Total lease liability, due 2020 | 8,185 |  |  | 8,490 |
Total lease liability, due 2021 | 5,727 |  |  | 7,496 |
Total lease liability, due 2022 | 3,965 |  |  | 5,105 |
Total lease liability, due 2023 | 2,900 |  |  | 3,641 |
Total lease liability, due after 2023 | 9,698 |  |  | 9,698 |
Total lease liability, total payments | 34,908 |  |  | $ 37,330 |
Total imputed interest | 3,463 |  |  |  |
Total lease liability | $ 31,445 |  |  |  |
[1] | Concurrent with the adoption of ASU 2016-02 discussed in Note 2. "Adoption of Accounting Pronouncements," finance lease obligations are now captured in Long-term debt on our Consolidated Balance Sheets.

X
- Definition [Line Items] for Amount of lessee's undiscounted obligation for lease payments for operating and finance leases. + References No definition available. + Details
Name: | sigi_LeaseLiabilitiesPaymentsDueLineItems
Namespace Prefix: | sigi_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments for both finance and operating leases. + References No definition available. + Details
Name: | sigi_TotalImputedInterest
Namespace Prefix: | sigi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Present value of lessee's discounted obligation for lease payments from finance and operating leases. + References No definition available. + Details
Name: | sigi_TotalLeaseLiability
Namespace Prefix: | sigi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payments for finance and operating leases, maturing in the fourth fiscal year following the latest fiscal year for all leases. + References No definition available. + Details
Name: | sigi_TotalLeasesDueInFourYears
Namespace Prefix: | sigi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payments for finance and operating leases, maturing in the third fiscal year following the latest fiscal year for all leases. + References No definition available. + Details
Name: | sigi_TotalLeasesDueInThreeYears
Namespace Prefix: | sigi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payments for finance and operating leases, maturing in the second fiscal year following the latest fiscal year for all leases + References No definition available. + Details
Name: | sigi_TotalLeasesDueInTwoYears
Namespace Prefix: | sigi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payments for finance and operating leases, maturing in the next fiscal year following the latest fiscal year for finance and operating leases. + References No definition available. + Details
Name: | sigi_TotalLeasesDueNext12Months
Namespace Prefix: | sigi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payments for finance and operating leases, due in remainder of fiscal year following latest fiscal year ended. + References No definition available. + Details
Name: | sigi_TotalLeasesDueRemainderoftheFiscalYear
Namespace Prefix: | sigi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payments for finance and operating leases, maturing after the fifth fiscal year following the latest fiscal year for all leases. + References No definition available. + Details
Name: | sigi_TotalLeasesDueThereafter
Namespace Prefix: | sigi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payments for finance and operating leases. + References No definition available. + Details
Name: | sigi_TotalMinimumPaymentRequired
Namespace Prefix: | sigi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Present value of lessee's discounted obligation for lease payments from finance lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977 + Details
Name: | us-gaap_FinanceLeaseLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payments for finance lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980 + Details
Name: | us-gaap_FinanceLeaseLiabilityPaymentsDue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payments for finance lease, due in next fiscal year following latest fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980 + Details
Name: | us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payments for finance lease, due in fifth fiscal year following latest fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980 + Details
Name: | us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payments for finance lease, due in fourth fiscal year following latest fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980 + Details
Name: | us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payments for finance lease, due in third fiscal year following latest fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980 + Details
Name: | us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payments for finance lease, due in second fiscal year following latest fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980 + Details
Name: | us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payments for finance lease, due in remainder of fiscal year following latest fiscal year ended. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980 + Details
Name: | us-gaap_FinanceLeaseLiabilityPaymentsRemainderOfFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments for finance lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980 + Details
Name: | us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payments for operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980 + Details
Name: | us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payments for operating lease, due in next fiscal year following latest fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980 + Details
Name: | us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payments for operating lease, due in fifth fiscal year following latest fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980 + Details
Name: | us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payments for operating lease, due in fourth fiscal year following latest fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980 + Details
Name: | us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payments for operating lease, due in third fiscal year following latest fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980 + Details
Name: | us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payments for operating lease, due in second fiscal year following latest fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980 + Details
Name: | us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payments for operating lease having an initial or remaining lease term in excess of one year due in remainder of fiscal year following latest fiscal year. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980 + Details
Name: | us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments for operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980 + Details
Name: | us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Present value of lessee's discounted obligation for lease payments from operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977 + Details
Name: | us-gaap_OperatingLeaseLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant