Certain Nontraditional Long-Duration Contracts (Changes in Deferred Sales Inducements, Reported as "Interest credited to policyholders' account (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
deferredsalesinducements
Deferred Sales Inducements, Beginning Balance	$ 590,515	$ 556,830
Deferred Sales Inducements, Ending Balance	$ 590,515	$ 556,830