Nature of Operations and Basis of Presentation (Details)	12 Months Ended
Dec. 31, 2018 state
Essent Guaranty
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of states in which the entity is licensed to write mortgage insurance	50
Affiliated Entity \| Essent Re \| Quota share reinsurance
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Reinsurance percentage	25.00%
Affiliated Entity \| Essent PA \| Reinsurance for mortgage insurance coverage in excess of 25%
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Reinsurance for mortgage insurance coverage threshold (as a percent)	25.00%
Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Residential mortgage down payment percentage for which mortgage insurance is generally required (percent) (less than)	20.00%

- Definition

Represents the percentage of the total sale price that a home buyer contributes in cash towards the purchase of a home for which mortgage insurance is generally required.

+ References

No definition available.

+ Details

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Namespace Prefix:	esnt_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Threshold percentage of risk reinsured on insurance products per entity policy.

+ References

No definition available.

+ Details

Name:	esnt_ReinsuranceRetentionPolicyReinsuredRiskPercentageThreshold
Namespace Prefix:	esnt_
Data Type:	num:percentItemType
Balance Type:	na
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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.

+ Details

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Data Type:	xbrli:stringItemType
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- Definition

The number of states the entity operates in as of the balance sheet date.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
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Period Type:	instant

- Definition

Percentage of risk reinsured on insurance products per entity policy.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

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- Details

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- Details

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Namespace Prefix:
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- Details

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- Details

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- Details

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- Details

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