Name:	pl_EstimatedOrdinaryDividendFromInsuranceSubsidiariesMaximum
Namespace Prefix:	pl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Represents the number of days after written notice to the insurance commissioner of the state of domicile within which ordinary dividends may be paid by insurance subsidiaries to the parent company.

No definition available.

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

Represents the entity's action level risk-based capital as of the balance sheet date.

No definition available.

Name:	pl_StatutoryAccountingPracticesActionLevelRiskBasedCapital
Namespace Prefix:	pl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Represents the amount of adjusted capital as of the balance sheet date.

No definition available.

Name:	pl_StatutoryAccountingPracticesAdjustedCapital
Namespace Prefix:	pl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

Name:	pl_StatutoryAccountingPracticesDisclosureOfFavorableUnfavorableEffectsOfPLICOsStatutorySurplusAbstract
Namespace Prefix:	pl_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

Name:	pl_StatutoryAccountingPracticesDisclosureOfFavorableUnfavorableEffectsOnStatutorySurplusOfInsuranceSubsidiariesAbstract
Namespace Prefix:	pl_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Statutory Accounting Practices, Gain (Loss) on Retrocession

No definition available.

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

Represents the amount of letters of credit as admitted assets to reconcile the differences as of the balance sheet date resulting from applying state permitted statutory accounting practices rather than statutory accounting practices permitted by National Association of Insurance Commissioners.

No definition available.

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

Represents the amount of non-admission of goodwill to reconcile the differences as of the balance sheet date resulting from applying state permitted statutory accounting practices rather than statutory accounting practices permitted by National Association of Insurance Commissioners.

No definition available.

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

Represents the amount of red mountain note as admitted assets to reconcile the differences as of the balance sheet date resulting from applying state permitted statutory accounting practices rather than statutory accounting practices permitted by National Association of Insurance Commissioners.

No definition available.

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

Represents the amount of reserving based on state specific actuarial practices to reconcile the differences as of the balance sheet date resulting from applying state permitted statutory accounting practices rather than statutory accounting practices permitted by National Association of Insurance Commissioners.

No definition available.

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

Represents the amount of reserving difference related to a captive insurance company to reconcile the differences as of the balance sheet date resulting from applying state permitted statutory accounting practices rather than statutory accounting practices permitted by National Association of Insurance Commissioners.

No definition available.

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

Represents the risk-based capital ratio as of the balance sheet date which is the ratio of a company's total adjusted capital, as defined by the insurance regulators, to its company action level of RBC.

No definition available.

Name:	pl_StatutoryAccountingPracticesRiskBasedCapitalRatio
Namespace Prefix:	pl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

The amount of consolidated stockholder's equity, excluding net unrealized gains on investments, which represents net assets of insurance subsidiaries of the entity that are restricted from transfer to the parent entity without prior approval from the state insurance department.

No definition available.

Name:	pl_StockholdersEquityRepresentingNetAssetsOfInsuranceSubsidiariesRestrictedFromTransferToParent
Namespace Prefix:	pl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Carrying amount of cash and investment securities on deposit with state regulatory authorities in connection with capital requirements.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 320
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=28366721&loc=d3e22002-158495

Name:	us-gaap_AssetsHeldByInsuranceRegulators
Namespace Prefix:	us-gaap_
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_StatutoryAccountingPracticesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount of each item listed to reconcile the differences as of the balance sheet date resulting from applying state permitted statutory accounting practices rather than statutory accounting practices permitted by National Association of Insurance Commissioners.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 505
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6486098&loc=d3e24746-158529

Name:	us-gaap_StatutoryAccountingPracticesPermittedPracticeAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The amount of statutory capital and surplus (stockholders' equity) as of the balance sheet date using prescribed or permitted statutory accounting practices (rather than GAAP, if different) of the state or country.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(23)(c))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 505
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6486098&loc=d3e24708-158529

Name:	us-gaap_StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of net income for the period determined using accounting principles prescribed or permitted by insurance regulators.