Policyholders' Liabilities - Schedule of Liability for Future Policy Benefits (Details) - USD ($) $ in Thousands		9 Months Ended
	Dec. 31, 2020	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Post-adoption liability, ending balance	$ 1,613,279
Life Insurance:
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Balance, beginning of year		$ 245,437	$ 274,467
Beginning balance at original discount rate		258,283	251,479
Effect of changes in cash flow assumptions				$ (172)	$ (3,425)
Effects of actual variances from expected experience				5,215	2,106
Adjusted beginning of year balance				263,326	250,160
Issuances		23,526	27,806
Interest accrual		7,145	6,291
Net premiums collected		(33,484)	(29,380)
Derecognition and other		807	535
Ending balance at original discount rate		261,320	255,412
Change in discount rate assumptions		(16,881)	(16,652)
Balance, end of period		244,439	238,760
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Pre-adoption liability, beginning balance		1,143,027	1,408,961
Beginning balance at original discount rate		1,204,220	1,198,026
Effect of changes in cash flow assumptions				(1,091)	(3,542)
Effects of actual variances from expected experience				9,827	5,519
Adjusted beginning of year balance				1,212,956	1,200,003
Issuances		24,158	28,402
Interest accrual		38,758	38,280
Benefit payments		(79,943)	(64,087)
Derecognition and other		139	(18)
Ending balance at original discount rate		1,196,068	1,202,580
Effect of changes in discount rates		(96,850)	(74,571)
Post-adoption liability, ending balance	1,249,202	1,099,218	1,128,009
Net liability for future policy benefits		854,779	889,249
Liability for Future Policy Benefits Net Premium Flooring Impact			2
Net liability for future policy benefits, after reinsurance recoverable			889,251
Home Service Insurance:
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Balance, beginning of year		106,763	114,752
Beginning balance at original discount rate		114,619	99,544
Effect of changes in cash flow assumptions				(258)	5,467
Effects of actual variances from expected experience				(10,108)	(5,902)
Adjusted beginning of year balance				104,253	99,109
Issuances		16,961	17,927
Interest accrual		3,367	2,719
Net premiums collected		(6,890)	(3,175)
Derecognition and other		588	(538)
Ending balance at original discount rate		118,279	116,042
Change in discount rate assumptions		(10,835)	(10,015)
Balance, end of period		107,444	106,027
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Pre-adoption liability, beginning balance		316,707	427,921
Beginning balance at original discount rate		336,096	322,765
Effect of changes in cash flow assumptions				74	6,587
Effects of actual variances from expected experience				(6,809)	165
Adjusted beginning of year balance				329,361	329,517
Issuances		16,969	17,938
Interest accrual		11,229	10,615
Benefit payments		(16,953)	(20,335)
Derecognition and other		573	(559)
Ending balance at original discount rate		341,179	337,176
Effect of changes in discount rates		(36,604)	(19,609)
Post-adoption liability, ending balance	$ 364,077	304,575	317,567
Net liability for future policy benefits		197,131	211,540
Liability for Future Policy Benefits Net Premium Flooring Impact			0
Net liability for future policy benefits, after reinsurance recoverable			211,540
Permanent | Life Insurance:
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Balance, beginning of year		235,228	269,528
Beginning balance at original discount rate		247,601	246,386
Effect of changes in cash flow assumptions				(210)	(3,662)
Effects of actual variances from expected experience				4,156	1,705
Adjusted beginning of year balance				251,547	244,429
Issuances		20,918	25,049
Interest accrual		6,897	6,259
Net premiums collected		(31,480)	(29,835)
Derecognition and other		567	445
Ending balance at original discount rate		248,449	246,347
Change in discount rate assumptions		(16,380)	(15,999)
Balance, end of period		232,069	230,348
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Pre-adoption liability, beginning balance		947,415	1,168,282
Beginning balance at original discount rate		996,169	990,921
Effect of changes in cash flow assumptions				(389)	(3,916)
Effects of actual variances from expected experience				6,338	2,127
Adjusted beginning of year balance				1,002,118	989,132
Issuances		21,360	25,567
Interest accrual		32,470	31,922
Benefit payments		(63,211)	(51,604)
Derecognition and other		97	(30)
Ending balance at original discount rate		992,834	994,987
Effect of changes in discount rates		(78,072)	(60,876)
Post-adoption liability, ending balance		914,762	934,111
Net liability for future policy benefits		682,693	703,763
Liability for Future Policy Benefits Net Premium Flooring Impact			2
Net liability for future policy benefits, after reinsurance recoverable			703,765
Permanent | Home Service Insurance:
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Balance, beginning of year		93,508	104,556
Beginning balance at original discount rate		100,225	90,012
Effect of changes in cash flow assumptions				(343)	4,253
Effects of actual variances from expected experience				(5,631)	(299)
Adjusted beginning of year balance				94,251	93,966
Issuances		13,854	13,886
Interest accrual		3,019	2,553
Net premiums collected		(8,909)	(8,331)
Derecognition and other		475	(655)
Ending balance at original discount rate		102,690	101,419
Change in discount rate assumptions		(9,438)	(8,386)
Balance, end of period		93,252	93,033
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Pre-adoption liability, beginning balance		200,351	266,206
Beginning balance at original discount rate		214,188	205,340
Effect of changes in cash flow assumptions				(257)	4,822
Effects of actual variances from expected experience				(5,472)	158
Adjusted beginning of year balance				208,459	210,320
Issuances		13,854	13,900
Interest accrual		6,987	6,539
Benefit payments		(12,246)	(15,058)
Derecognition and other		464	(669)
Ending balance at original discount rate		217,518	215,032
Effect of changes in discount rates		(23,934)	(14,624)
Post-adoption liability, ending balance		193,584	200,408
Net liability for future policy benefits		100,332	107,375
Liability for Future Policy Benefits Net Premium Flooring Impact			0
Net liability for future policy benefits, after reinsurance recoverable			107,375
Permanent Limited Pay | Life Insurance:
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Balance, beginning of year		10,209	4,939
Beginning balance at original discount rate		10,682	5,093
Effect of changes in cash flow assumptions				38	237
Effects of actual variances from expected experience				1,059	401
Adjusted beginning of year balance				11,779	5,731
Issuances		2,608	2,757
Interest accrual		248	32
Net premiums collected		(2,004)	455
Derecognition and other		240	90
Ending balance at original discount rate		12,871	9,065
Change in discount rate assumptions		(501)	(653)
Balance, end of period		12,370	8,412
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Pre-adoption liability, beginning balance		195,612	240,679
Beginning balance at original discount rate		208,051	207,105
Effect of changes in cash flow assumptions				(702)	374
Effects of actual variances from expected experience				3,489	3,392
Adjusted beginning of year balance				210,838	210,871
Issuances		2,798	2,835
Interest accrual		6,288	6,358
Benefit payments		(16,732)	(12,483)
Derecognition and other		42	12
Ending balance at original discount rate		203,234	207,593
Effect of changes in discount rates		(18,778)	(13,695)
Post-adoption liability, ending balance		184,456	193,898
Net liability for future policy benefits		172,086	185,486
Liability for Future Policy Benefits Net Premium Flooring Impact			0
Net liability for future policy benefits, after reinsurance recoverable			185,486
Permanent Limited Pay | Home Service Insurance:
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Balance, beginning of year		13,255	10,196
Beginning balance at original discount rate		14,394	9,532
Effect of changes in cash flow assumptions				85	1,214
Effects of actual variances from expected experience				(4,477)	(5,603)
Adjusted beginning of year balance				10,002	5,143
Issuances		3,107	4,041
Interest accrual		348	166
Net premiums collected		2,019	5,156
Derecognition and other		113	117
Ending balance at original discount rate		15,589	14,623
Change in discount rate assumptions		(1,397)	(1,629)
Balance, end of period		14,192	12,994
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Pre-adoption liability, beginning balance		116,356	161,715
Beginning balance at original discount rate		121,908	117,425
Effect of changes in cash flow assumptions				331	1,765
Effects of actual variances from expected experience				(1,337)	7
Adjusted beginning of year balance				$ 120,902	$ 119,197
Issuances		3,115	4,038
Interest accrual		4,242	4,076
Benefit payments		(4,707)	(5,277)
Derecognition and other		109	110
Ending balance at original discount rate		123,661	122,144
Effect of changes in discount rates		(12,670)	(4,985)
Post-adoption liability, ending balance		110,991	117,159
Net liability for future policy benefits		$ 96,799	104,165
Liability for Future Policy Benefits Net Premium Flooring Impact			0
Net liability for future policy benefits, after reinsurance recoverable			$ 104,165