Fixed-maturity Securities in Default (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Investments [Abstract]
Available-for-sale fixed-maturity securities in default, amortized cost	$ 258	$ 3,983
Available-for-sale fixed-maturity securities in default, fair value	$ 720	$ 5,168

Available-for-sale fixed-maturity securities in default, amortized cost

No definition available.

Name:	pri_AvailableForSaleFixedMaturitySecuritiesInDefaultAmortizedCost
Namespace Prefix:	pri_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant