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Loss Reserves - Prior Year Loss Reserves (Details) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |
Total prior year loss development | $ (208,514) | $ (404,130) | $ (60,015)
Increase (decrease) in estimated claim rate on primary defaults |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |
Total prior year loss development | (200,983) | (400,577) | (82,904)
Change in estimates related to severity on primary defaults, pool reserves, LAE reserves, reinsurance, and other |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |
Total prior year loss development | $ (7,531) | $ (3,553) | $ 22,889

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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 -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480081/944-40-50-3 + Details
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