MORTGAGE LOANS - Change in Allowance for Credit Losses (Details) - Commercial mortgage loans - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2019	Dec. 31, 2018
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	$ 1,296	$ 0
Charge offs	(350)	0
Recoveries	0	(209)
Provision	3,110	1,505
Ending Balance	$ 4,056	$ 1,296

Financing Receivable, Allowance for Credit Losses, Charge Offs

No definition available.

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Namespace Prefix:	plico_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

+ References

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

- Definition

Amount of recovery of financing receivables doubtful of collection that were previously charged off.

+ References

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-Publisher FASB
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+ Details

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

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- 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

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	debit
Period Type:	duration

- Details

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