Schedule II - Financial Information of Registrant - Parent Company Statement of Cash Flows (Details) - USD ($) $ in Thousands		12 Months Ended
	Feb. 09, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities
Net cash provided by (used in) operating activities		$ 388,298	$ 557,112	$ 658,434
Proceeds from sales of:
Fixed-maturities available for sale		399,371	735,340	963,589
Trading securities		8,868	7,952	11,602
Proceeds from redemptions of:
Fixed-maturities available for sale		789,929	1,225,626	645,068
Purchases of:
Fixed-maturities available for sale		(1,414,966)	(1,980,155)	(2,449,762)
Equity securities		(24,637)	(105,649)	(85,014)
Sales, redemptions and (purchases) of:
Short-term investments, net		150,694	68,083	(82,925)
Other assets and other invested assets, net		(6,887)	6,126	1,434
Net cash provided by (used in) investing activities		(5,175)	(1,862)	(883,180)
Cash flows from financing activities
Dividends and dividend equivalents paid		(135,437)	(103,298)	(97,458)
Issuance of common stock		1,341	1,382	1,553
Repurchases of common stock	$ (400,000)	(400,195)	(399,100)	(226,305)
Issuance of senior notes, net		0	0	515,567
Credit facility commitment fees paid		(814)	(3,325)	(2,292)
Change in secured borrowings, net (with terms three months or less)		60,270	1,057	0
Net cash provided by (used in) financing activities		(479,183)	(496,776)	222,618
Increase (decrease) in cash and restricted cash		(96,060)	58,474	(2,128)
Cash and restricted cash, beginning of period		152,620	94,146	96,274
Cash and restricted cash, end of period		56,560	152,620	94,146
Parent Company
Cash flows from operating activities
Net cash provided by (used in) operating activities		(71)	66,317	(13,741)
Proceeds from sales of:
Fixed-maturities available for sale		56,934	195,452	304,737
Trading securities		8,868	0	0
Equity securities		0	0	13,401
Proceeds from redemptions of:
Fixed-maturities available for sale		194,859	301,788	238,161
Purchases of:
Fixed-maturities available for sale		(29,039)	(156,344)	(691,874)
Equity securities		(2,500)	0	0
Sales, redemptions and (purchases) of:
Short-term investments, net		188,149	113,939	(53,024)
Other assets and other invested assets, net		(3,851)	(864)	(6,068)
Capital distributions from subsidiaries		32,512	44,951	19,000
Capital contributions to subsidiaries		(8,000)	(43,250)	(5,050)
Net cash provided by (used in) investing activities		437,932	455,672	(180,717)
Cash flows from financing activities
Dividends and dividend equivalents paid		(135,437)	(103,298)	(97,458)
Issuance of common stock		1,341	1,382	1,553
Repurchases of common stock		(400,195)	(399,100)	(226,305)
Issuance of senior notes, net		0	0	515,567
Credit facility commitment fees paid		(814)	(3,325)	(2,292)
Net cash provided by (used in) financing activities		(474,835)	(503,284)	191,065
Increase (decrease) in cash and restricted cash		(36,974)	18,705	(3,393)
Cash and restricted cash, beginning of period		38,846	20,141	23,534
Cash and restricted cash, end of period		1,872	38,846	20,141
Cash distributions received from consolidated subsidiaries		49,800	85,000	1,700
Dividends received from consolidated subsidiaries		$ 888,000	$ 92,300	$ 484,100