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Subsequent Events (Details) - Subsequent Event $ in Thousands	Apr. 01, 2022 USD ($)
Subsequent Event [Line Items]
Subsequent Event, Date	Apr. 01, 2022
Federal Home Loan Bank Advances	$ 35,000
Selective Insurance Company of America | Zero Point Seventy Percent Borrowing from FHLBNY Due May 2, 2022. [Member]
Subsequent Event [Line Items]
Federal Home Loan Bank, Advances, Interest Rate	0.70%
Selective Insurance Company of America | One Point Ten Percent Borrowing from FHLBNY Due June 27, 2022. [Member]
Subsequent Event [Line Items]
Federal Home Loan Bank, Advances, Interest Rate	1.10%

X

- Definition

Amount of advances from the Federal Home Loan Bank (FHLB).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822

+ Details

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X

- Definition

Interest rate of advances made and reported by Federal Home Loan Bank (FHLBank).

+ References

No definition available.

+ Details

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X

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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X

- Definition

Date the event occurred after the balance sheet date but before financial statements are issues or available to be issued, in YYYY-MM-DD format.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 855
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6842918&loc=SL6314017-165662

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- Details

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X

- Details

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X

- Details

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- Details

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