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Reserve for Loss and Loss Expense (Reserve Loss Development) (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Favorable or adverse loss development | $ (82,853) | $ (72,932) |
Favorable or unfavorable loss development [Member] |  |  |
Favorable or adverse loss development | (82,900) | (72,900) | $ (50,300)
Favorable or unfavorable loss development [Member] | Casualty Insurance Product Line [Member] |  |  |
Favorable or adverse loss development | (81,000) | (85,000) | (61,000)
Favorable or unfavorable loss development [Member] | Casualty Insurance Product Line [Member] | Commercial Automobile [Member] |  |  |
Favorable or adverse loss development | 15,000 | 10,000 |
Favorable or unfavorable loss development [Member] | Property Insurance [Member] |  |  |
Favorable or adverse loss development | 1,900 | 12,100 | 10,700
Favorable or unfavorable loss development [Member] | Property Insurance [Member] | Commercial Automobile [Member] |  |  |
Favorable or adverse loss development | 13,300 | 7,100 |
Favorable or unfavorable loss development [Member] | General Liability [Member] |  |  |
Favorable or adverse loss development | (29,000) | (35,000) | (5,000)
Favorable or unfavorable loss development [Member] | Commercial Automobile [Member] |  |  |
Favorable or adverse loss development | 13,300 | 7,100 | 700
Favorable or unfavorable loss development [Member] | Workers Compensation [Member] |  |  |
Favorable or adverse loss development | (58,000) | (60,000) | (68,000)
Favorable or unfavorable loss development [Member] | Business Owners' Policies [Member] |  |  |
Favorable or adverse loss development | (400) | 3,900 | 1,900
Favorable or unfavorable loss development [Member] | Commercial Property [Member] |  |  |
Favorable or adverse loss development | (2,600) | 9,200 | 5,100
Favorable or unfavorable loss development [Member] | Homeowners [Member] |  |  |
Favorable or adverse loss development | 1,800 | 7,700 | 7,500
Favorable or unfavorable loss development [Member] | Personal Automobile [Member] |  |  |
Favorable or adverse loss development | (200) | (1,800) | 4,400
Favorable or unfavorable loss development [Member] | E&S Casualty Lines [Member] |  |  |
Favorable or adverse loss development | (7,000) | 0 | 2,000
Favorable or unfavorable loss development [Member] | E&S Property Lines [Member] |  |  |
Favorable or adverse loss development | (800) | (4,000) | 1,000
Favorable or unfavorable loss development [Member] | Insurance, Other [Member] |  |  |
Favorable or adverse loss development | $ 0 | $ 0 | $ 100

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- Definition Amount, after effects of reinsurance, of expense (reversal of expense) for claims incurred in prior reporting periods and related claims settlement costs. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=116884095&loc=d3e14764-158437 + Details
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