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Reserve for Losses and Loss Adjustment Expenses - Prior year development (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2022 | Jun. 30, 2021 | Jun. 30, 2022 | Jun. 30, 2021
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) | $ 171,226 | $ 59,250 | $ 313,038 | $ 100,922
Operating segments | Insurance |  |  |  |
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) | $ 6,700 | $ 4,000 | $ 14,000 | $ 8,100
Percentage of prior year development | 0.60% | 0.50% | 0.70% | 0.50%
Operating segments | Insurance | Short tailed lines |  |  |  |
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) | $ 14,300 |  | $ 33,200 | $ 49,400
Operating segments | Insurance | Short tailed lines | Property excluding marine |  |  |  |
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) |  | $ 7,100 |  | 21,600
Operating segments | Insurance | Short tailed lines | Travel and accident |  |  |  |
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) |  | 6,700 |  | 9,300
Operating segments | Insurance | Short tailed lines | Lenders products |  |  |  |
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) | 12,200 | 10,700 | 30,800 | 18,600
Operating segments | Insurance | Medium tailed lines |  |  |  |
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) |  | (24,500) |  | (45,400)
Operating segments | Insurance | Medium tailed lines | Programs |  |  |  |
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) |  |  | 5,200 | (12,600)
Operating segments | Insurance | Medium tailed lines | Professional liability |  |  |  |
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) | (6,300) |  | (13,600) | (11,200)
Operating segments | Insurance | Medium tailed lines | Contract binding |  |  |  |
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) |  | (20,100) | (6,100) | (20,100)
Operating segments | Insurance | Medium tailed lines | Marine |  |  |  |
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) | 2,600 |  | 5,500 |
Operating segments | Insurance | Long tailed lines | Construction and national accounts |  |  |  |
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) |  | 5,600 | (7,600) |
Operating segments | Insurance | Long tailed lines | Executive assurance |  |  |  |
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) | (5,700) |  |  |
Operating segments | Insurance | Medium tailed and long tailed lines |  |  |  |
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) | (7,500) |  | (19,200) |
Operating segments | Insurance | Short Tailed And Long Tailed Lines |  |  |  |
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) |  | 28,500 |  | 53,500
Operating segments | Reinsurance |  |  |  |
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) | $ 46,400 | $ 20,500 | $ 78,900 | $ 47,300
Percentage of prior year development | 5.00% | 2.80% | 4.60% | 3.40%
Operating segments | Reinsurance | Short tailed lines |  |  |  |
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) |  |  | $ 74,900 | $ 67,200
Operating segments | Reinsurance | Short tailed lines | Property catastrophe |  |  |  |
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) | $ 6,300 | $ (17,100) | 9,700 | (39,600)
Operating segments | Reinsurance | Short tailed lines | Property Other Than Property Catastrophe |  |  |  |
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) | 31,600 |  | 47,400 | 28,800
Operating segments | Reinsurance | Short tailed lines | Other specialty lines |  |  |  |
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) | 13,100 | 61,600 | 18,000 | 78,200
Operating segments | Reinsurance | Medium tailed lines | Marine and aviation |  |  |  |
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) | 4,200 | 4,000 | 14,900 |
Operating segments | Reinsurance | Long tailed lines |  |  |  |
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) | (8,000) | (33,200) | (10,900) | (24,800)
Operating segments | Reinsurance | Long tailed lines | Casualty |  |  |  |
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) |  | (34,200) |  |
Operating segments | Reinsurance | Short tailed and medium tailed lines |  |  |  |
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) | 54,400 | 53,700 | 89,700 | 72,100
Operating segments | Mortgage |  |  |  |
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) | $ 118,100 | $ 43,100 | $ 220,200 | $ 54,000
Percentage of prior year development | 39.90% | 12.90% | 37.60% | 8.10%
Operating segments | Other |  |  |  |
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Prior year development favorable (unfavorable) |  | $ (8,300) |  | $ (8,400)

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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 https://asc.fasb.org/extlink&oid=116884095&loc=d3e14764-158437 + Details
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