XML 133 R114.htm IDEA: XBRL DOCUMENT v3.10.0.1

Share-Based Transactions - Summary of Activity Related to Stock Options Outstanding and Exercisable (Parenthetical) (Details)	12 Months Ended
	Dec. 31, 2018 $ / shares
$41.20 (average term remaining - 5.1 years) Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vested option exercise price	$ 41.20
Vested option exercise, average life	5 years 1 month 6 days
$53.50 (average term remaining - 6.2 years) Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vested option exercise price	$ 53.50
Vested option exercise, average life	6 years 2 months 12 days
$41.88 (average term remaining - 7.1 years) Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vested option exercise price	$ 41.88
Vested option exercise, average life	7 years 1 month 6 days

X

- Definition

Share based compensation shares authorized under stock option plans exercise price range outstanding and exercisable options weighted average exercise price.

+ References

No definition available.

+ Details

Name:	pri_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingAndExercisableOptionsWeightedAverageExercisePrice
Namespace Prefix:	pri_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Share based compensation shares authorized under stock option plans exercise price range outstanding and exercisable weighted average remaining contractual term.

+ References

No definition available.

+ Details

Name:	pri_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingAndExercisableWeightedAverageRemainingContractualTerm
Namespace Prefix:	pri_
Data Type:	xbrli:durationItemType
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

- Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=pri_RangeOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=pri_RangeTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=pri_RangeThreeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: