Certain Long-Duration Contracts with Guarantees (Sales Inducements) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Movement in Deferred Sales Inducements [Roll Forward]
Beginning balance	$ 684,844	$ 836,791	$ 989,889
Capitalization	932	6,462	9,112
Amortization-Impact of assumption and experience unlocking and true-ups	11,817	21,829	34,420
Amortization-All other	(144,670)	(183,843)	(194,673)
Change in unrealized investment gains (losses)	(2,802)	3,605	(1,957)
Other	(550,121)
Ending balance	$ 0	$ 684,844	$ 836,791