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Loss Reserves - Prior Year Loss Reserves (Details) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |
Prior years | $ (71,006) | $ (167,366) | $ (231,204)
Decrease in estimated claim rate on primary delinquencies |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |
Prior years | (112,000) | (213,000) | (248,000)
(Decrease) increase in estimated severity on primary delinquencies |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |
Prior years | (1,000) | 29,000 | 9,000
Change in estimates related to pool reserves, LAE reserves, reinsurance and other |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |
Prior years | $ 42,000 | $ 17,000 | $ 8,000

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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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