Represents the expected payments under support agreement obligation.

No definition available.

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

- Definition

Represents the future scheduled capital contributions to prefund credit enhancement fees under support agreement obligation.

+ References

No definition available.

+ Details

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

- Definition

Represents the term of the letter of credit of the entity.

+ References

No definition available.

+ Details

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

- Definition

Represents the maximum amount up to which the borrowing capacity under the letter of credit arrangements will be increased.

+ References

No definition available.

+ Details

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

- Definition

Represents the maximum borrowing capacity under the letters of credit.

+ References

No definition available.

+ Details

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

- Definition

Represents the number of installments in which future scheduled capital contributions are payable under support agreement obligation.

+ References

No definition available.

+ Details

Name:	pl_NumberOfInstallmentsInWhichFutureScheduledCapitalContributionsIsPayable
Namespace Prefix:	pl_
Data Type:	xbrli:integerItemType
Balance Type:	na
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_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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

- Details

Name:	dei_LegalEntityAxis=pl_GoldenGateIIIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=us-gaap_SuccessorMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=pl_GoldenGateIVMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

DEBT AND OTHER OBLIGATIONS - Letters of Credit (Details) $ in Millions	8 Months Ended
	Sep. 30, 2015 USD ($) installment	Mar. 31, 2016 USD ($)	Jun. 25, 2014 USD ($)	Aug. 07, 2013 USD ($)	Dec. 10, 2010 USD ($)	Apr. 23, 2010 USD ($)
Golden Gate III
Debt Instrument [Line Items]
Maximum borrowing capacity under letter of credit			$ 915.0	$ 710.0		$ 505.0
Maximum amount up to which LOC will be periodically increased			$ 935.0	$ 720.0		$ 610.0
Letter of credit term	15 years
Future scheduled capital contributions	$ 122.5
Number of installments in which future scheduled capital contributions payable \| installment	3
Golden Gate III \| Successor
Debt Instrument [Line Items]
Outstanding letters of credit (LOC)		$ 935.0
Payments under support agreement obligation		0.0
Golden Gate IV
Debt Instrument [Line Items]
Maximum borrowing capacity under letter of credit					$ 270.0
Maximum amount up to which LOC will be periodically increased		790.0
Letter of credit term	12 years
Golden Gate IV \| Successor
Debt Instrument [Line Items]
Maximum borrowing capacity under letter of credit		780.0
Payments under support agreement obligation		$ 0.0