Segment and Geographical Information - Summary of Assets and Profit or Loss by Segment (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Revenues		$ 2,720,133	$ 2,709,732	$ 2,217,541
Net investment income		93,065	80,588	83,814
Amortization of deferred policy acquisition costs		356,143	251,179	224,321
Non-cash share-based compensation expense		22,361	16,842	19,027
Income (loss) before income taxes		493,749	511,171	506,730
Assets		15,348,877	16,123,223	14,905,285
Term Life Insurance Segment [Member]
Segment Reporting Information [Line Items]
Revenues		1,687,126	1,575,686	1,382,770
Net investment income		51,160	36,486	27,030
Amortization of deferred policy acquisition costs		342,925	241,451	216,208
Non-cash share-based compensation expense		4,133	4,153	3,612
Income (loss) before income taxes		448,540	414,619	372,551
Assets		7,175,746	7,274,820	6,985,086
Investment and Savings Products Segment [Member]
Segment Reporting Information [Line Items]
Revenues		863,432	941,847	718,867
Amortization of deferred policy acquisition costs		12,141	8,668	7,055
Non-cash share-based compensation expense		3,212	3,206	3,045
Income (loss) before income taxes		239,330	274,585	202,644
Assets	[1]	2,415,041	2,920,271	2,769,445
Senior Health Segment [Member]
Segment Reporting Information [Line Items]
Revenues		62,682	60,440
Non-cash share-based compensation expense		210
Income (loss) before income taxes		(98,673)	(85,050)
Assets		431,993	528,974
Corporate and Other Distributed Products Segment [Member]
Segment Reporting Information [Line Items]
Revenues		106,893	131,759	115,904
Net investment income		41,905	44,102	56,784
Amortization of deferred policy acquisition costs		1,077	1,060	1,058
Non-cash share-based compensation expense		14,806	9,483	12,370
Income (loss) before income taxes		(95,448)	(92,983)	(68,465)
Assets		$ 5,326,097	$ 5,399,158	$ 5,150,754

[1] The Investment and Savings Products segment includes assets held in separate accounts. Excluding separate accounts, the Investment and Savings Products segment assets were $109.3 million, $120.3 million, and $110.0 million as of December 31, 2022, 2021, and 2020, respectively.