Deferred Acquisition Costs and Value of Business Acquired (Details 2) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Deferred acquisition costs and value of business acquired
Deferred acquisition costs	$ 172,416	$ 177,781	$ 158,526	$ 253,038
As previously reported | Adoption of ASU No. 2010-26
Deferred acquisition costs and value of business acquired
Deferred acquisition costs				143,550
Retrospective adoption | Adoption of ASU No. 2010-26
Deferred acquisition costs and value of business acquired
Deferred acquisition costs				$ 396,588