MORTGAGE LOANS - Delinquent Loans (Details) - Commercial mortgage loans $ in Thousands	6 Months Ended	12 Months Ended
Jun. 30, 2017 USD ($) loan	Dec. 31, 2016 USD ($) loan
Delinquent loans
Past due period at which to cease carrying accrued interest on delinquent loans	90 days
Past due period at which to initiate foreclosure proceedings	90 days
Commercial mortgage loans \| $	$ 8,245	$ 3,669
Number of delinquent commercial mortgage loans \| loan	5	4
30-59 Days Delinquent
Delinquent loans
Commercial mortgage loans \| $	$ 5,440	$ 3,669
Number of delinquent commercial mortgage loans \| loan	3	4
60 to 89 Days Delinquent
Delinquent loans
Commercial mortgage loans \| $	$ 0	$ 0
Number of delinquent commercial mortgage loans \| loan	0	0
Greater than 90 Days Delinquent
Delinquent loans
Commercial mortgage loans \| $	$ 2,805	$ 0
Number of delinquent commercial mortgage loans \| loan	2	0

Represents the minimum number of days over which the entity's policy is to initiate foreclosure proceedings.

No definition available.

Name:	plico_FinancingReceivableMinimumNumberOfDaysPastDueToInitiateForeclosureProceedings
Namespace Prefix:	plico_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of financing receivables that are past due at the balance sheet date.

+ References

No definition available.

+ Details

Name:	plico_FinancingReceivableNumberOfLoansPastDue
Namespace Prefix:	plico_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The maximum number of days of accrued interest that can be carried on an impaired loan.

+ References

No definition available.

+ Details

Name:	plico_MaximumNumberOfDaysAccruedInterestOnImpairedLoans
Namespace Prefix:	plico_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Recorded Investment in financing receivables that are past due at the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7A
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953401-111524

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentPastDue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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_FinancingReceivableRecordedInvestmentPastDueLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

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

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivables30To59DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivables60To89DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: