Summary of Investments (Net Realized Investment Gains and Losses) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Gain (Loss) on Investments [Line Items]
Net realized investment gains (losses)	$ 1,300	$ 1,219	$ 4,658	$ 4,996
Available-for-sale Securities [Abstract]
Proceeds from sales	0	830	12,003	21,871
Gross realized gains	0	793	472	1,144
Gross realized losses	0	0	25	688
Fixed Maturities [Member]
Gain (Loss) on Investments [Line Items]
Net realized investment gains (losses)	102	813	2,425	3,247
Equity Securities [Member]
Gain (Loss) on Investments [Line Items]
Net realized investment gains (losses)	0	792	697	2,126
Trading Securities [Member]
Gain (Loss) on Investments [Line Items]
Net realized investment gains (losses)	1,198	(457)	1,536	(179)
Other Long-term Investments [Member]
Gain (Loss) on Investments [Line Items]
Net realized investment gains (losses)	0	(78)	0	(347)
Mark-to-market Valuation Gain for Interest Rate Swap [Member]
Gain (Loss) on Investments [Line Items]
Net realized investment gains (losses)	$ 0	$ 149	$ 0	$ 149