Segment and Geographical Information - Summary of Assets and Profit or Loss by Segment (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Segment Reporting Information [Line Items]
Revenues		$ 691,226	$ 637,711
Net investment income		18,905	20,052
Amortization of deferred policy acquisition costs		86,063	66,105
Non-cash share-based compensation expense		12,437	11,653
Income (loss) before income taxes		103,003	128,309
Assets		15,934,813		$ 16,123,223
Term Life Insurance Segment [Member]
Segment Reporting Information [Line Items]
Revenues		418,428	382,027
Net investment income		11,445	8,253
Amortization of deferred policy acquisition costs		81,883	62,584
Non-cash share-based compensation expense		2,125	1,988
Income (loss) before income taxes		91,577	88,236
Assets		7,298,577		7,274,820
Investment and Savings Products Segment [Member]
Segment Reporting Information [Line Items]
Revenues		241,039	223,422
Amortization of deferred policy acquisition costs		3,925	3,275
Non-cash share-based compensation expense		1,204	1,208
Income (loss) before income taxes		64,560	63,363
Assets	[1]	2,818,660		2,920,271
Senior Health Segment [Member]
Segment Reporting Information [Line Items]
Revenues		5,831
Income (loss) before income taxes		(23,085)
Assets		511,010		528,974
Corporate and Other Distributed Products Segment [Member]
Segment Reporting Information [Line Items]
Revenues		25,928	32,262
Net investment income		7,460	11,799
Amortization of deferred policy acquisition costs		255	246
Non-cash share-based compensation expense		9,108	8,457
Income (loss) before income taxes		(30,049)	$ (23,290)
Assets		$ 5,306,566		$ 5,399,158

[1] The Investment and Savings Products segment includes assets held in separate accounts. Excluding separate accounts, the Investment and Savings Products segment assets were $121.8 million and $120.3 million as of March 31, 2022 and December 31, 2021, respectively.