Name:	pl_GuarantorObligationsMaximumExposurePerAgreement
Namespace Prefix:	pl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Income tax refunds expected as a result of accepted IRS adjustments.

No definition available.

Name:	pl_IncomeTaxRefundsExpectedIrsAdjustments
Namespace Prefix:	pl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Represents the number of putative class action lawsuits that were filed and subsequently consolidated by the court.

No definition available.

Name:	pl_NumberOfPutativeClassActionLawsuitsFiledConsolidated
Namespace Prefix:	pl_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Additional income tax cash payments required if the entity's appeal to the IRS is denied relating to IRS proposed adjustments to the entity's taxable income for prior years.

No definition available.

Name:	pl_PotentialAdditionalIncomeTaxCashPayments
Namespace Prefix:	pl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

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_LossContingenciesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The total number of new claims filed pertaining to a loss contingency during the period.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14435-108349