Investments (Other Invested Assets) (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Other Investments [Line Items]
Other invested assets	$ 1,110,107	$ 1,198,319
Equity securities
Other Investments [Line Items]
Other invested assets	127,668	126,860
Limited Partner [Member]
Other Investments [Line Items]
Other invested assets	492,465	446,604
Structured loans
Other Investments [Line Items]
Other invested assets	52,185	164,309
Derivatives
Other Investments [Line Items]
Other invested assets	194,276	216,966
Fair Value Option Contractholder Directed Unit Linked Investments [Member]
Other Investments [Line Items]
Other invested assets	137,529	140,344
Other
Other Investments [Line Items]
Other invested assets	$ 105,984	$ 103,236