Deferred Policy Acquisition Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Balance, beginning of year	$ 1,613,922	$ 1,376,211	$ 1,341,093
Capitalization of commissions, sales and issue expenses	451,773	346,885	278,892
Amortization-Impact of assumption and experience unlocking and true-ups	(34,619)	(54,772)	(16,140)
Amortization-All other	(78,699)	(81,054)	(78,867)
Change in unrealized investment gains and losses	(37,337)	26,652	(5,363)
Other	(59,342)	0	(143,404)
Balance, end of year	$ 1,855,698	$ 1,613,922	$ 1,376,211