Consolidated Balance Sheets (Parenthetical)(USD ($)) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Consolidated Balance Sheets [Abstract]
Amortized costs of fixed maturity investments available for sale, at fair value	$ 226,397	$ 828,544
Trading securities, Amortized Cost	6,207,991	5,714,322
Equity securities, amortized cost	$ 356,370	$ 160,513
Common shares, issued	40,003,642	40,003,642
Common shares, outstanding	37,742,131	38,089,226
Treasury stock, shares	2,261,511	1,914,416