Segment Information - Narrative (Details) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) segments	Jun. 30, 2015 USD ($)
Segment Reporting Information [Line Items]
Number of segments | segments				2
Net results from structured products	[1]	$ 2,059	$ 5,257	$ 4,029	$ 10,282
Net investment income | Total P&C
Segment Reporting Information [Line Items]
Net results from structured products		14,100	16,000	26,700	31,100
Interest Expense [Member] | Total P&C
Segment Reporting Information [Line Items]
Net results from structured products		$ (12,000)	$ (10,600)	$ (22,700)	$ (20,600)

[1] The net results from P&C structured products include net investment income and interest expense of $26.7 million and $22.7 million, respectively.