Segment Information - Narrative (Details) $ in Thousands	6 Months Ended	12 Months Ended
Dec. 31, 2023 segment	Dec. 31, 2023 USD ($) segment program employee
Segment Reporting Information [Line Items]
Number of reportable segments	4	4
Number of operating segments		4
Syndicate 1729
Segment Reporting Information [Line Items]
Proceeds from sale of ownership interest \| $		$ 6,800
Proportion of capital provided to support Lloyd's syndicate (percent)	5.00%	5.00%
Workers' Compensation Insurance
Segment Reporting Information [Line Items]
Number of employees \| employee		1,000
Alternative market solutions percentage ceded	100.00%	100.00%
Number of programs \| program		2

Alternative Market Solutions Percentage Ceded

No definition available.

Name:	pra_AlternativeMarketSolutionsPercentageCeded
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Balance Type:	na
Period Type:	instant

- Definition

Number Of Programs

+ References

No definition available.

+ Details

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Namespace Prefix:	pra_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

This item represents the capital provided in support of a segment by a corporate member as a percentage of total capital provided by all members to support the segment.

+ References

No definition available.

+ Details

Name:	pra_ProportionOfCapitalProvidedToSupportSegment
Namespace Prefix:	pra_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Workers Compensation Products, Maximum Number of Employees

+ References

No definition available.

+ Details

Name:	pra_WorkersCompensationProductsMaximumNumberOfEmployees
Namespace Prefix:	pra_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-18

+ Details

Name:	us-gaap_NumberOfOperatingSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

+ Details

Name:	us-gaap_NumberOfReportableSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash inflow resulting from the sale of an interest in a corporate unit during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 14
-Subparagraph (a)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482740/230-10-45-14

+ Details

Name:	us-gaap_ProceedsFromSaleOfInterestInCorporateUnit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- 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

Name:	us-gaap_SegmentReportingInformationLineItems
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

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Namespace Prefix:
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Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=pra_WorkersCompensationInsuranceSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: