4. Sources of Changes in Net Unrealized Investment (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Sources Of Changes In Net Unrealized Investment Details
Debt securities	$ 45,860	$ 16,845	$ 66,239	$ 30,416
Other investments	(48)	163	(8)	270
Net unrealized investment gains	45,812	17,008	66,231	30,686
Applicable deferred policy acquisition cost	18,445	11,436	27,183	16,113
Applicable deferred income tax expense (benefit)	9,578	(6,299)	13,666	(549)
Offsets to net unrealized investment gains	28,023	5,137	40,849	15,564
Net unrealized investment gains (losses) included in OCI	$ 17,789	$ 11,871	$ 25,382	$ 15,122