Deferred Policy Acquisition Costs - Balances and Activity in DAC Roll Forward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Deferred Policy Acquisition Cost [Line Items]
DAC balance, beginning of period	$ 3,188,502
Amortization	(275,816)	$ (261,629)	$ (238,270)
DAC balance, end of period	3,447,234	3,188,502
Term Life [Member]
Deferred Policy Acquisition Cost [Line Items]
DAC balance, beginning of period	3,106,148	2,869,812
Capitalization	521,718	507,834
Amortization	(268,803)	(254,875)
Foreign exchange translation and other	7,218	(16,623)
DAC balance, end of period	3,366,281	3,106,148	2,869,812
Segregated Funds (Canada) [Member]
Deferred Policy Acquisition Cost [Line Items]
DAC balance, beginning of period	62,341	65,411
Capitalization	4,353	7,003
Amortization	(5,479)	(5,581)
Foreign exchange translation and other	1,814	(4,492)
DAC balance, end of period	$ 63,029	$ 62,341	$ 65,411