Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Statement of Comprehensive Income [Abstract]
Net income	$ 1,161,238	$ 1,070,762	$ 970,755
Unrealized gains (losses) on fixed maturities:
Unrealized holding gains (losses) arising during period	429,290	(630,042)	671,211
Other reclassification adjustments included in net income	14,714	3,764	80,238
Foreign exchange adjustment on fixed maturities recorded at fair value	(1,427)	3,469	(715)
Total unrealized investment gains (losses)	442,577	(622,809)	750,734
Less applicable tax (expense) benefit	(92,941)	130,787	(157,658)
Unrealized gains (losses) on investments, net of tax	349,636	(492,022)	593,076
Future Policy benefits:
Change in discount rate on future policy benefits	(142,514)	1,567,530	(731,883)
Less applicable tax (expense) benefit	29,928	(329,181)	153,696
Future policy benefit adjustments, net of tax	(112,586)	1,238,349	(578,187)
Foreign exchange translation:
Foreign exchange translation adjustments, other than securities	16,094	(33,516)	8,102
Less applicable tax (expense) benefit	(3,381)	7,040	(1,702)
Foreign exchange translation adjustments, other than securities, net of tax	12,713	(26,476)	6,400
Pension:
Amortization of pension costs	253	474	(390)
Plan amendments	0	(1,212)	0
Experience gain (loss)	10,522	29,659	(3,907)
Pension adjustments	10,775	28,921	(4,297)
Less applicable tax (expense) benefit	(2,262)	(6,073)	902
Pension adjustments, net of tax	8,513	22,848	(3,395)
Other comprehensive income (loss)	258,276	742,699	17,894
Comprehensive income (loss)	$ 1,419,514	$ 1,813,461	$ 988,649