Adjustment relating to recovery of financing receivables.

No definition available.

Name:	pl_FinancingReceivableAllowanceForCreditLossesRecoveryAdjustment
Namespace Prefix:	pl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the amount of nonperforming loans, foreclosed properties, and restructured loans pursuant to pooling and servicing agreements.

+ References

No definition available.

+ Details

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

- Definition

Represents the number of categories of loans.

+ References

No definition available.

+ Details

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

- Definition

Represents the amount of nonperforming mortgage loans, foreclosed properties and restructured loans pursuant to a pooling and servicing agreement, as a percent of invested assets.

+ References

No definition available.

+ Details

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

- Definition

Represents the amount of financing receivables not subject to a pooling and servicing agreement that are nonperforming or have been restructured under the terms and conditions of the pooling and service agreement.

+ References

No definition available.

+ Details

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

- Definition

Represents the amount of financing receivables subject to a pooling and servicing agreement that are nonperforming or have been restructured under the terms and conditions of the pooling and service agreement.

+ References

No definition available.

+ Details

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

- Definition

Represents the principal amount of loans accounted for as troubled debt restructurings satisfied during the period by acceptance or agreement to accept assets.

+ References

No definition available.

+ Details

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

- Definition

Represents the loan-to-value ratio permitted on commercial mortgage loans in exchange for a participating interest in the cash flows from the underlying property.

+ References

No definition available.

+ Details

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

- Definition

Represents the amount of mortgage loans as of the balance sheet date which have a feature providing the entity a participating interest in the cash flows from the underlying real estate.

+ References

No definition available.

+ Details

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

- Definition

Represents the amount of assets the entity accepted or agreed to accept on mortgage loans accounted for as troubled debt restructurings during the period which have a feature providing the entity a participating interest in the cash flows from the underlying real estate.

+ References

No definition available.

+ Details

Name:	pl_MortgageLoansOnRealEstateParticipatingLoansAccountedForAsTroubledDebtRestructuringsAssetsAccepted
Namespace Prefix:	pl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the amount of income earned during the period on mortgage loans, which have a feature providing the entity a participating interest in the cash flows from the underlying real estate.

+ References

No definition available.

+ Details

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

- Definition

Represents the number of nonperforming financing receivables subject to a pooling and servicing agreement, which have been restructured under the terms and conditions of the pooling and servicing agreement.

+ References

No definition available.

+ Details

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

- Definition

A valuation allowance for financing receivables that are expected to be uncollectible.

+ References

+ Details

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

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

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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

- Definition

Amount of direct write-downs of financing receivables charged against the allowance.

+ References

+ Details

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

- Definition

Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (c)(2)

-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953423-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-04.11)

-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585

+ Details

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

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=pl_CommercialMortgageLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=us-gaap_PredecessorMember
Namespace Prefix:
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MORTGAGE LOANS (Details 2)	1 Months Ended	3 Months Ended		8 Months Ended	9 Months Ended	12 Months Ended
MORTGAGE LOANS (Details 2)	Jan. 31, 2015 USD ($) loan	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) loan item	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Mortgage loans
Number of nonperforming loans which have been restructured \| loan				0
Change in the allowance for credit losses
Charge offs				$ (535,000)
Recoveries				(639,000)
Provision				3,199,000
Ending balance		$ 2,025,000		2,025,000
Commercial mortgage loans
Mortgage loans
Mortgage loans having participation feature		562,600,000		562,600,000
Income recognized on participating mortgage loans		3,300,000		8,400,000
Nonperforming mortgage loans, foreclosed properties and restructured loans pursuant to pooling and servicing agreements		$ 7,300,000		$ 7,300,000
Nonperforming mortgage loans, foreclosed properties and restructured loans to invested assets (as a percent)		0.02%		0.02%
Assets accepted or agreed to be accepted on mortgage loans accounted for as troubled debt restructurings				$ 12,100,000
Principal amount of loans accounted for as troubled debt restructurings satisfied by acceptance of assets				$ 15,200,000
Number of loan categories \| item				2
Loans not subject to a pooling and servicing agreement which are either nonperforming or restructured		$ 7,300,000		$ 7,300,000
Loans subject to a pooling and servicing agreement which are either nonperforming or restructured		$ 0		$ 0
Commercial mortgage loans \| Maximum
Mortgage loans
Loan-to-value ratio with participating interest (as a percent)		85.00%		85.00%
Predecessor
Mortgage loans
Number of nonperforming loans which have been restructured \| loan	0
Predecessor \| Commercial mortgage loans
Mortgage loans
Mortgage loans having participation feature						$ 553,600,000
Income recognized on participating mortgage loans	$ 100,000		$ 8,000,000		$ 13,800,000
Assets accepted or agreed to be accepted on mortgage loans accounted for as troubled debt restructurings	11,300,000
Principal amount of loans accounted for as troubled debt restructurings satisfied by acceptance of assets	13,800,000
Change in the allowance for credit losses
Beginning balance	5,720,000			$ 2,500,000	$ 3,130,000	3,130,000
Charge offs	(861,000)					(675,000)
Recoveries	(2,359,000)					(2,600,000)
Provision						5,865,000
Ending balance	$ 2,500,000					$ 5,720,000