Reinsurance - Variable Interest Entity (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2020	Dec. 31, 2019	Oct. 30, 2020
Home Re special purpose insurers
Effects of Reinsurance [Line Items]
Amortization period excess of loss reinsurance coverage	10 years
Term of mortgage insurance-linked notes	10 years
Remaining First Layer Retention	$ 351,043	$ 353,415
Remaining Excess of Loss Reinsurance Coverages	$ 426,489	531,978
Percent of total trust assets invested in cash or direct U.S. federal government obligations	99.50%
Home Re special purpose insurers \| Subsequent Event
Effects of Reinsurance [Line Items]
Remaining Excess of Loss Reinsurance Coverages			$ 412,900
Home Re 2018-1
Effects of Reinsurance [Line Items]
Remaining First Layer Retention	$ 166,246	167,779
Remaining Excess of Loss Reinsurance Coverages	218,343	260,957
Total VIE Assets	218,343	269,451
Home Re 2019-1
Effects of Reinsurance [Line Items]
Remaining First Layer Retention	184,797	185,636
Remaining Excess of Loss Reinsurance Coverages	208,146	271,021
Total VIE Assets	$ 208,146	$ 283,150

Amortization Period Excess of Loss Reinsurance Coverage

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- Definition

Reinsurance Retention Policy, Debt Issued To Cover Insurance, Term

+ References

No definition available.

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- Definition

Reinsurance Retention Policy, Percent Of Total Trust Assets Invested In Cash Or Direct U.S. Federal Government Obligations

+ References

No definition available.

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- Definition

Reinsurance Retention Policy, Remaining Excess of Loss Reinsurance Coverages

+ References

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- Definition

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.

+ References

No definition available.

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- Definition

Stated amount that is the upper retention limit per entity policy.

+ References

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- Definition

Carrying amount of the assets in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the Variable Interest Entity (VIE), where the reporting entity is not the VIE's primary beneficiary.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph a
-URI http://asc.fasb.org/extlink&oid=118582676&loc=d3e5728-111685

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