Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Net income	$ 185,345	$ 173,600
Investments:
Total unrealized investment gains (losses)	694,939	(615,682)
Less applicable tax (expense) benefit	(145,936)	129,289
Unrealized investment gains (losses), net of tax	549,003	(486,393)
Deferred acquisition costs:
Unrealized gains (losses) attributable to deferred acquisition costs	(3,199)	450
Less applicable tax (expense) benefit	671	(94)
Unrealized gains (losses) attributable to deferred acquisition costs, net of tax	(2,528)	356
Foreign exchange translation:
Foreign exchange translation adjustments, other than fixed maturities	3,089	(1,299)
Less applicable tax (expense) benefit	(647)	276
Foreign exchange translation adjustments, other than fixed maturities, net of tax	2,442	(1,023)
Pension:
Amortization of pension costs	2,120	3,778
Less applicable tax (expense) benefit	(445)	(793)
Pension adjustments, net of tax	1,675	2,985
Other comprehensive income (loss)	550,592	(484,075)
Comprehensive income (loss)	735,937	(310,475)
Securities [Member]
Investments:
Unrealized holding gains (losses) arising during period	693,482	(611,548)
Reclassification adjustments included in net income	(2,444)	(696)
Foreign exchange adjustment on fixed maturities recorded at fair value	(142)	(585)
Unrealized gains (losses) on fixed maturities	690,896	(612,829)
Other Investments [Member]
Investments:
Unrealized gains (losses) on other investments	$ 4,043	$ (2,853)