Deferred Policy Acquisition Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Balance, beginning of year	$ 749,302	$ 1,114,431	$ 1,345,504
Capitalization of commissions, sales and issue expenses	269,679	1,535	2,804
Amortization-Impact of assumption and experience unlocking and true-ups	226,204	33,113	91,895
Amortization-All other	(46,388)	(342,265)	(330,311)
Changes in unrealized investment gains and losses	18,772	16,352	4,539
Ceded DAC upon Reinsurance Treaty with Prudential Insurance	(7,480)	(73,864)	0
Assumed DAC upon Reinsurance Treaty with Pruco Life	3,134,272	0	0
Balance, end of year	4,344,361	$ 749,302	$ 1,114,431
True-up to the ceded DAC upon reinsurance agreement with Prudential Insurance	$ 7,500