Investments (Other Invested Assets) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Other invested assets	$ 1,777,065	$ 1,298,120
Equity securities
Other invested assets	420,248	125,862
Limited Partner [Member]
Other invested assets	671,577	567,697
Derivatives
Other invested assets	310,168	256,178
Fair Value Option Contractholder Directed Unit Linked Investments [Member]
Other invested assets	200,208	197,547
Other
Other invested assets	$ 174,864	$ 150,836