5. GMDB Benefits By Type (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2012	Dec. 31, 2011
Account Value	$ 2,136,851	$ 2,200,264
Net Amount at Risk After Reinsurance	88,799	141,401
Return of premium
Account Value	788,804	825,573
Net Amount at Risk After Reinsurance	12,275	21,576
Average Attained Age Of Annuitant	62 years	62 years
Step up
Account Value	1,282,770	1,307,870
Net Amount at Risk After Reinsurance	68,182	110,666
Average Attained Age Of Annuitant	63 years	62 years
Earnings enhancement benefit ("EEB")
Account Value	38,591	39,715
Net Amount at Risk After Reinsurance	168	400
Average Attained Age Of Annuitant	63 years	62 years
Greater of annual step up and roll up
Account Value	26,686	27,106
Net Amount at Risk After Reinsurance	$ 8,174	$ 8,759
Average Attained Age Of Annuitant	66 years	66 years