Segment Information (Details) - Narrative (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012 segments		Jun. 30, 2011
Segment Reporting Information [Line Items]
Number of Operating Segments					3
Net results from structured products	$ (13,866)	[1]	$ 4,916	[1]	$ (8,549)	[1]	$ 12,390	[1]
Total P And C Segment [Member]
Segment Reporting Information [Line Items]
Net results from structured products	(13,866)	[1]	4,916	[1]	(8,549)	[1]	12,390	[1]
Total P And C Segment [Member] | Net Investment Income [Member]
Segment Reporting Information [Line Items]
Net results from structured products	17,400		18,400		34,700	[1]	38,100
Total P And C Segment [Member] | Interest Expense [Member]
Segment Reporting Information [Line Items]
Net results from structured products	$ (31,300)		$ (13,500)		$ (43,200)		$ (25,700)

[1] The net results from P&C structured products include net investment income and interest expense.