Name:	pl_FinancingReceivableMinimumNumberOfDaysPastDueForCeasingAccrualOfInterest
Namespace Prefix:	pl_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Represents the minimum number of days past due at which the entity's policy is to initiate foreclosure proceedings.

No definition available.

Name:	pl_FinancingReceivableMinimumNumberOfDaysPastDueToInitiateForeclosureProceedings
Namespace Prefix:	pl_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Represents the number of financing receivables that are past due at the balance sheet date.

No definition available.

Name:	pl_FinancingReceivableNumberOfLoansPastDue
Namespace Prefix:	pl_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Recorded Investment in financing receivables that are past due at the balance sheet date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 7A

-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953401-111524

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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.

No definition available.

Name:	us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems
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Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=pl_CommercialMortgageLoanMember
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Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivables30To59DaysPastDueMember
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Period Type:

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivables60To89DaysPastDueMember
Namespace Prefix:
Data Type:	na
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Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember
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