Investments (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012 securities	Dec. 31, 2011 securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities in unrealized loss position, number of positions	38	76
Available-for-sale securities, estimated fair value	$ 271,205	$ 587,887
Gross unrealized losses	(17,531)	(17,670)
Number of available-for-sale securities positions in a continuous unrealized loss position for greater than one year at period end	10	17
Available-for-sale securities, estimated fair value, 12 months or longer	9,993	45,786
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, aggregate losses	(507)	(2,355)
Fixed Maturities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, estimated fair value	25,226	176,302
Gross unrealized losses	(9,473)	(13,520)
Number of available-for-sale securities positions in a continuous unrealized loss position for greater than one year at period end	8	16
Available-for-sale securities, estimated fair value, 12 months or longer	8,022	27,261
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, aggregate losses	(372)	(2,349)
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, estimated fair value	84,988	115,594
Gross unrealized losses	(8,056)	(4,146)
Number of available-for-sale securities positions in a continuous unrealized loss position for greater than one year at period end	2	1
Available-for-sale securities, estimated fair value, 12 months or longer	1,971	18,525
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, aggregate losses	$ (135)	$ (6)