Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data	Sep. 30, 2011	Dec. 31, 2010
Consolidated Balance Sheets [Abstract]
Fixed maturities, available for sale, amortized cost	$ 4,882,036	$ 4,533,233
Equity securities, available for sale, cost	$ 19,906	$ 20,765
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	75,000,000	75,000,000
Common stock, shares issued	61,792,029	61,469,148
Treasury stock, shares	21,873,322	21,813,196