Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies - Summary of Restated Permanent and Temporary Stockholders' Equity from Date of Apotion (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022	Dec. 31, 2021
Balance, beginning of period		$ 2,009,534	$ 911,330	$ 911,330
Accounting standards update [extensible enumeration]		us-gaap:AccountingStandardsUpdate201812Member
Repurchases of common stock	$ (85,300)
Net income		$ 125,106	115,039
Net income (loss) attributable to noncontrolling interests			(2,655)
Balance, end of period	1,921,101	1,921,101	1,434,895	2,009,534	$ 911,330
Common Stock [Member]
Balance, beginning of period		368	394	394	393
Net issuance of common stock		2	1	2	2
Repurchases of common stock		(6)	(7)	(28)	(1)
Balance, end of period	364	364	388	368	394
Paid-in Capital [Member]
Balance, beginning of period			5,224	5,224
Share-based compensation		16,622	14,820	33,624	31,043
Net issuance of common stock		(2)	(1)	(2)	(2)
Repurchases of common stock		(16,620)	(20,043)	(41,079)	(25,817)
Redemption of noncontrolling interest in consolidated entities				2,233
Balance, end of period					5,224
Retained Earnings [Member]
Balance, beginning of period		2,130,935	2,074,111	2,074,111	1,682,939
Repurchases of common stock		(80,360)	(83,813)	(320,332)
Net income		125,106	115,039	460,939	465,808
Dividends		(23,910)	(21,645)	(83,783)	(74,636)
Balance, end of period	2,151,771	2,151,771	2,083,692	2,130,935	2,074,111
Accumulated Other Comprehensive Income (Loss), Net of Income Tax [Member]
Balance, beginning of period		(121,769)	(1,168,399)	(1,168,399)	(1,380,912)
Effect of change in discount rate assumptions on the liability for future policy benefits		(142,974)	646,141	1,372,022	269,895
Change in foreign currency translation adjustment		998	3,289	(20,747)	6,973
Change in net unrealized investment gains (losses) during the period		32,711	(130,216)	(304,645)	(64,355)
Balance, end of period	$ (231,034)	(231,034)	(649,185)	(121,769)	(1,168,399)
Redeemable Noncontrolling Interests in Consolidated Entities/Temporary Stockholders' Equity [Member]
Balance, beginning of period			7,271	7,271
Acquisition of noncontrolling interest					8,438
Net income (loss) attributable to noncontrolling interests			(2,655)	(5,038)	(1,377)
Change in noncontrolling interests in consolidated entities, net					210
Redemption of noncontrolling interest in consolidated entities				(2,233)
Balance, end of period			4,616		7,271
As Previously Reported [Member]
Balance, beginning of period		1,721,499
Net income			81,419
Net income (loss) attributable to noncontrolling interests			(2,655)
Balance, end of period				1,721,499
As Previously Reported [Member] | Retained Earnings [Member]
Balance, beginning of period			2,074,111	2,074,111	1,705,786
Balance, end of period					2,074,111
As Previously Reported [Member] | Accumulated Other Comprehensive Income (Loss), Net of Income Tax [Member]
Balance, beginning of period			$ (1,168,399)	$ (1,168,399)	129,706
Balance, end of period					(1,168,399)
Adoption Impacts [Member]
Balance, beginning of period		$ 288,035
Accounting standards update [extensible enumeration]			us-gaap:AccountingStandardsUpdate201812Member	us-gaap:AccountingStandardsUpdate201812Member
Net income			$ 33,620
Balance, end of period				$ 288,035
Cumulative Effect, Period of Adoption, Adjustment [Member] | Adoption Impacts [Member] | Retained Earnings [Member]
Balance, beginning of period					$ (22,847)
Accounting standards update [extensible enumeration]				us-gaap:AccountingStandardsUpdate201812Member	us-gaap:AccountingStandardsUpdate201812Member
Balance, end of period
Cumulative Effect, Period of Adoption, Adjustment [Member] | Adoption Impacts [Member] | Accumulated Other Comprehensive Income (Loss), Net of Income Tax [Member]
Balance, beginning of period					$ (1,510,618)
Accounting standards update [extensible enumeration]				us-gaap:AccountingStandardsUpdate201812Member	us-gaap:AccountingStandardsUpdate201812Member
Balance, end of period