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Related Party Transactions (Narrative) (Details) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013
Equity ownership percentage of director of parent of general independent retail insurance agency | 10.00% |  |
Direct premiums written | $ 2,403,519 | $ 2,228,270 | $ 2,133,793
Contributions to the Selective Insurance Group Foundation | 1,000 | 800 | 400
Related Party Insurance Agency [Member] |  |  |
Direct premiums written | 9,600 | 9,000 | 8,200
Commissions paid to Rue Insurance | $ 1,700 | $ 1,600 | $ 1,300

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- Definition The minimum percentage of the equity of an independent insurance agency owned by a director of the Parent. + References No definition available. + Details
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- Definition The amount of contributions made to a related party private foundation. + References No definition available. + Details
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- Definition Amount, before premiums ceded to other entities and premiums assumed by the entity, of premiums written. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 605 -Section 50 -Paragraph 1 -Subparagraph (b),(c)(1) -URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 17 -Article 12 + Details
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- Definition The amount of cash paid for commissions during the current period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 25 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3536-108585 + Details
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- Details
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