COMMITMENTS AND CONTINGENCIES (Details) (USD $)	0 Months Ended
Jun. 03, 2014 item	Mar. 31, 2015
Indemnification Agreement
Commitments and contingencies
Indemnification agreement with certain officers, maximum		$ 10,000,000
IRS proposed adjustment
Commitments and contingencies
Additional income tax cash payments if IRS prevails on every issue		26,600,000
Merger Agreement
Commitments and contingencies
Number of lawsuits filed	4
Number of putative class action lawsuits filed	$ 3

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under each individual guarantee agreement.

No definition available.

+ Details

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

- Definition

Represents the number of putative class action lawsuits that were filed.

+ References

No definition available.

+ Details

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

- Definition

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.

+ References

No definition available.

+ Details

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

- Details

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

- Definition

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

+ References

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

+ Details

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Balance Type:	na
Period Type:	duration

- Details

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Namespace Prefix:
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- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: