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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Percentage of risk reinsured on insurance products per entity policy.

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Amount of cash restricted as to withdrawal or usage. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits.

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Reinsurance - Narrative (Details) $ in Thousands		9 Months Ended	12 Months Ended
Reinsurance - Narrative (Details) $ in Thousands	Apr. 01, 2019 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2020 USD ($) quotaShareAgreement	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Ceded Credit Risk [Line Items]
Restricted cash		$ 2,662	$ 5,555	$ 2,662
Number of quota share agreements \| quotaShareAgreement			3
Reinsurance recoverable on unpaid claims		$ 4,939	$ 17,608	4,939	$ 3,001	$ 1,902
ILN Transactions
Ceded Credit Risk [Line Items]
Reinsurance coverage, term of underlying mortgage amortization (in years)			10 years
Optional termination right, percent of reinsurance coverage threshold			10.00%
QSR Transactions
Ceded Credit Risk [Line Items]
Ceding commissions under QSR Transaction			20.00%
2018 QSR Transaction
Ceded Credit Risk [Line Items]
Threshold for loss ratio on loans to qualify for profit commission			61.00%
2016 QSR Transaction
Ceded Credit Risk [Line Items]
Threshold for loss ratio on loans to qualify for profit commission			60.00%
2020 QSR Transaction
Ceded Credit Risk [Line Items]
Threshold for loss ratio on loans to qualify for profit commission			50.00%
Third-Party Reinsurers \| 2017 ILN Transaction
Ceded Credit Risk [Line Items]
Risk premiums paid			$ 22,800	$ 14,600	$ 9,600
Third-Party Reinsurers \| 2018 QSR Transaction
Ceded Credit Risk [Line Items]
Reinsurance recoverable on unpaid claims			$ 12,600
Third-Party Reinsurers \| Risk Written Policies in 2018
Ceded Credit Risk [Line Items]
Premiums of premiums earned under QSR Transaction				25.00%
Third-Party Reinsurers \| Risk Written Policies in 2019
Ceded Credit Risk [Line Items]
Percent of premiums ceded under QSR Transaction			20.00%
Third-Party Reinsurers \| 2016 QSR Transaction
Ceded Credit Risk [Line Items]
Percent of premiums ceded under QSR Transaction		20.50%	25.00%
Previously Ceded Primary Risk-In-Force Recaptured	$ 500,000
Reinsurance recoverable on unpaid claims			$ 4,500
Third-Party Reinsurers \| Existing Risk Written Policies
Ceded Credit Risk [Line Items]
Percent of premiums ceded under QSR Transaction					25.00%
Third-Party Reinsurers \| Fannie Mae
Ceded Credit Risk [Line Items]
Percent of premiums ceded under QSR Transaction			100.00%
Third-Party Reinsurers \| 2020 QSR Transaction
Ceded Credit Risk [Line Items]
Reinsurance recoverable on unpaid claims			$ 500
Third-Party Reinsurers \| Risk written in 2020
Ceded Credit Risk [Line Items]
Premiums of premiums earned under QSR Transaction			21.00%
Third-Party Reinsurers \| Maximum \| 2017 ILN Transaction
Ceded Credit Risk [Line Items]
Anticipated payment related to annual operating expenses			$ 300
Third-Party Reinsurers \| Maximum \| 2018 ILN Transaction
Ceded Credit Risk [Line Items]
Anticipated payment related to annual operating expenses			$ 250