Schedule IV. Reinsurance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Life insurance in force, gross amount	$ 227,975,584	$ 225,286,002	$ 222,098,389
Life insurance in force, ceded to other companies	671,056	685,289	662,569
Life insurance in force, assumed from other companies	1,823,957	1,996,223	2,172,728
Life insurance in force, net amount	$ 229,128,485	$ 226,596,936	$ 223,608,548
Life insurance in force, percentage of amount assumed to net	0.80%	0.90%	1.00%
Premium, gross amount	$ 4,619,824	$ 4,391,558	$ 4,238,135
Premium, ceded to other companies	7,098	7,317	7,452
Premium, assumed from other companies	41,288	58,877	66,019
Premium, net amount	$ 4,654,014	$ 4,443,118	$ 4,296,702
Percentage of amount assumed to net	0.90%	1.30%	1.50%
Policy charges	$ 12,300	$ 12,900	$ 13,500
Life insurance
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Premium, gross amount	3,235,744	3,109,838	2,999,637
Premium, ceded to other companies	4,649	4,597	4,361
Premium, assumed from other companies	17,994	19,104	19,009
Premium, net amount	$ 3,249,089	$ 3,124,345	$ 3,014,285
Percentage of amount assumed to net	0.60%	0.60%	0.60%
Health insurance
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Premium, gross amount	$ 1,384,080	$ 1,281,720	$ 1,238,498
Premium, ceded to other companies	2,449	2,720	3,091
Premium, assumed from other companies	23,294	39,773	47,010
Premium, net amount	$ 1,404,925	$ 1,318,773	$ 1,282,417
Percentage of amount assumed to net	1.70%	3.00%	3.70%