Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net income	$ 178,724	$ 153,334	$ 536,749	$ 427,148
Investments:
Total unrealized investment gains (losses)	(164,122)	72,071	(1,205,609)	684,066
Less applicable tax (expense) benefit	34,464	(25,225)	253,176	(239,479)
Unrealized investment gains (losses), net of tax	(129,658)	46,846	(952,433)	444,587
Deferred acquisition costs:
Unrealized gains (losses) attributable to deferred acquisition costs	1,178	505	3,669	(992)
Less applicable tax (expense) benefit	(248)	(177)	(771)	347
Unrealized gains (losses) attributable to deferred acquisition costs, net of tax	930	328	2,898	(645)
Foreign exchange translation:
Foreign exchange translation adjustments, other than securities	(168)	8,533	(7,684)	16,049
Less applicable tax (expense) benefit	36	(2,986)	1,615	(4,567)
Foreign exchange translation adjustments, other than securities, net of tax	(132)	5,547	(6,069)	11,482
Pension:
Amortization of pension costs	3,778	3,108	11,334	9,326
Experience gain (loss)	0	0	0	371
Pension adjustments	3,778	3,108	11,334	9,697
Less applicable tax (expense) benefit	(793)	(1,087)	(2,380)	(3,393)
Pension adjustments, net of tax	2,985	2,021	8,954	6,304
Other comprehensive income (loss)	(125,875)	54,742	(946,650)	461,728
Comprehensive income (loss)	52,849	208,076	(409,901)	888,876
Securities [Member]
Investments:
Unrealized holding gains (losses) arising during period	(173,598)	83,216	(1,202,762)	692,747
Reclassification adjustment for (gains) losses on securities included in net income	(1,510)	(12,910)	(12,327)	(13,264)
Reclassification adjustment for amortization of (discount) and premium	1,052	119	2,612	(379)
Foreign exchange adjustment on securities recorded at fair value	8,624	1,173	7,360	1,418
Unrealized gains (losses) on securities	(165,432)	71,598	(1,205,117)	680,522
Other Investments [Member]
Investments:
Unrealized gains (losses) on other investments	$ 1,310	$ 473	$ (492)	$ 3,544

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