Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Statement of Financial Position [Abstract]
Amortized cost on fixed maturities trading investments	$ 2,318,100	$ 2,345,620
Cost - equity security trading investments	458,690	388,417
Cost - short-term investments	$ 221,163	$ 236,433
Common Stock
Common stock, no par value	$ 0	$ 0
Common stock, shares authorized	70,000,000	70,000,000
Common stock, shares issued	54,911,000	54,856,000
Common stock, shares outstanding	54,911,000	54,856,000