Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024
Statement of Cash Flows [Abstract]
Cash provided from (used for) operating activities	$ 1,045,790	$ 1,065,513
Investments sold or matured:
Fixed maturities available for sale—sold	456,567	674,125
Fixed maturities available for sale—matured or other redemptions	217,427	161,275
Mortgage loans	19,742	29,433
Other long-term investments	82,337	29,995
Total investments sold or matured	776,073	894,828
Acquisition of investments:
Fixed maturities—available for sale	(775,630)	(1,000,665)
Mortgage loans	(118,572)	(134,667)
Other long-term investments	(88,296)	(445,776)
Total investments acquired	(982,498)	(1,581,108)
Net (increase) decrease in policy loans	(29,872)	(34,052)
Net (increase) decrease in short-term investments	22,211	(18,761)
Additions to property and equipment	(121,979)	(56,047)
Other investing activities	0	96
Investments in low-income housing interests	(41,709)	(27,840)
Cash provided from (used for) investing activities	(377,774)	(822,884)
Cash provided from (used for) financing activities:
Issuance of common stock	145,569	34,851
Cash dividends paid to shareholders	(64,394)	(65,292)
Proceeds from issuance of debt	0	530,000
Payment for debt issuance costs	(6,399)	(7,138)
Net borrowing from Federal Home Loan Bank (FHLB)	65,000	17,000
Net borrowing (repayment) of commercial paper	1,870	31,443
Proceeds from commercial paper with original maturities greater than 90 days	442,040	387,247
Repayment of commercial paper with original maturities greater than 90 days	(529,962)	(314,836)
Acquisition of treasury stock	(688,719)	(950,448)
Net receipts (payments) from deposit-type products	107,951	122,291
Cash provided from (used for) financing activities	(527,044)	(214,882)
Effect of foreign exchange rate changes on cash	(3,581)	3,646
Net increase (decrease) in cash	137,391	31,393
Cash at beginning of year	165,325	103,156
Cash at end of period	$ 302,716	$ 134,549