Debt Instrument, Outstanding Principal

No definition available.

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

- Definition

Extinguishment of Debt, Par Value

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility which can be granted upon request by the entity.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Balance Type:	na
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

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the aggregate of total long-term debt, including current maturities and short-term debt.

+ References

No definition available.

+ Details

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

- Definition

Gross amount of debt extinguished.

+ References

No definition available.

+ Details

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

- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=49170532&loc=d3e12317-112629

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=49170532&loc=d3e12355-112629

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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

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

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.16)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.16)
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19, 20, 22
-Article 5

+ Details

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

- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

+ References

No definition available.

+ Details

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

- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of subordinated debt (with initial maturities beyond one year or beyond the operating cycle if longer). Subordinated debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets.

+ References

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 210.7-03.16)
-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 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.16)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Article 5
-Subsection 19, 20, 22

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 10
-Section F

+ Details

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

- Details

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- Details

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- Details

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- Details

Name:	us-gaap_DebtInstrumentAxis=pl_SeniorNotes7.375PercentDue2019Member
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- Details

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- Details

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DEBT AND OTHER OBLIGATIONS - Summary of Debt and Subordinated Debt Securities (Details) - USD ($)			9 Months Ended	11 Months Ended
	Feb. 03, 2015	Feb. 02, 2015	Sep. 30, 2016	Dec. 31, 2015	Jun. 30, 2016
6.125% Subordinated Debentures (2004), due 2034, callable 2009
Debt Instrument [Line Items]
Stated interest rate (as a percent)			6.125%
2015 Credit Facility
Debt Instrument [Line Items]
Line of credit, maximum borrowing capacity		$ 1,000,000,000.0
Line of credit, maximum borrowing capacity to be granted upon entity's request		$ 1,250,000,000
Base of floating rate interest rate payments		LIBOR
Facility fee percentage	0.125%	0.15%
Successor
Debt Instrument [Line Items]
Debt			$ 1,385,284,000	$ 1,588,806,000
Subordinated debt securities			443,122,000	448,763,000
Successor \| 6.40% Senior Notes (2007), due 2018
Debt Instrument [Line Items]
Debt			158,178,000	162,671,000
Debt, outstanding principal			$ 150,000,000	$ 150,000,000
Stated interest rate (as a percent)			6.40%	6.40%
Successor \| 7.375% Senior Notes (2009), due 2019
Debt Instrument [Line Items]
Debt			$ 459,339,000	$ 473,127,000
Debt, outstanding principal			$ 400,000,000	$ 400,000,000
Stated interest rate (as a percent)			7.375%	7.375%
Successor \| 8.45% Senior Notes (2009), due 2039
Debt Instrument [Line Items]
Debt			$ 382,767,000	$ 468,008,000
Debt, outstanding principal			246,926,000	$ 300,000,000
Extinguishment of debt			82,700,000
Par value of debt extinguished			$ 53,100,000
Stated interest rate (as a percent)			8.45%	8.45%
Pre-tax gain on extinguishment of debt			$ 9,800,000
Successor \| 6.25% Subordinated Debentures (2012), due 2042, callable 2017
Debt Instrument [Line Items]
Debt, outstanding principal			287,500,000	$ 287,500,000
Subordinated debt securities			$ 291,482,000	$ 295,833,000
Stated interest rate (as a percent)			6.25%	6.25%
Successor \| 6.00% Subordinated Debentures (2012), due 2042, callable 2017
Debt Instrument [Line Items]
Debt, outstanding principal			$ 150,000,000	$ 150,000,000
Subordinated debt securities			$ 151,640,000	$ 152,930,000
Stated interest rate (as a percent)			6.00%	6.00%
Successor \| 6.125% Subordinated Debentures (2004), due 2034, callable 2009
Debt Instrument [Line Items]
Repayment of debt				$ 103,100,000
Successor \| Credit Facility
Debt Instrument [Line Items]
Debt			$ 385,000,000	$ 485,000,000
Successor \| 2015 Credit Facility
Debt Instrument [Line Items]
Line of credit, amount outstanding			$ 385,000,000
Prime Rate \| 2015 Credit Facility
Debt Instrument [Line Items]
Base of floating rate interest rate payments		Prime rate
Federal Funds Rate \| 2015 Credit Facility
Debt Instrument [Line Items]
Base of floating rate interest rate payments		Funds rate
Interest rate added to the base rate (as a percent)		0.50%
LIBOR One-Month Rate \| 2015 Credit Facility
Debt Instrument [Line Items]
Base of floating rate interest rate payments		one-month LIBOR
Interest rate added to the base rate (as a percent)		1.00%
LIBOR \| Successor \| 2015 Credit Facility
Debt Instrument [Line Items]
Base of floating rate interest rate payments			LIBOR
Interest rate added to the base rate (as a percent)			1.00%
PLICO \| Successor \| Letter of Credit
Debt Instrument [Line Items]
Outstanding letters of credit (LOC)					$ 30,000,000