XML 130 R111.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Share-Based Transactions - Employee Share-Based Transactions, PSU Activity (Parenthetical) (Details) - Performance share units (PSUs) [Member] - ROAE Achieved Within Vesting Period [Member] - shares | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Maximum number of shares of common stock may be received by recipients | 45,869,000 | 54,069,000 | 22,758,000
Minimum number of shares of common stock may be received by recipients | 0 | 0 |

X
- Definition Share based compensation arrangement by share based payment award minimum number of shares per employee. + References No definition available. + Details
Name: | pri_ShareBasedCompensationArrangementByShareBasedPaymentAwardMinimumNumberOfSharesPerEmployee
Namespace Prefix: | pri_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- 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_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The highest quantity of shares an employee can purchase under the plan per period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumNumberOfSharesPerEmployee
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_PerformanceSharesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VestingAxis=pri_ReturnOnAdjustedEquityAchievedWithinVestingPeriodMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |