Schedule II Financial Information of Registrant - Parent Company Statement of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities
Net cash provided by (used in) operating activities	$ 557,112	$ 658,434	$ 694,431
Cash flows from investing activities
Fixed-maturities available for sale	735,340	963,589	986,647
Trading securities	7,952	11,602	130,537
Fixed-maturities available for sale	1,225,626	645,068	464,777
Trading securities	16,668	22,913	37,684
Fixed-maturities available for sale	1,980,155	2,449,762	1,913,703
Short-term investments, net	68,083	(82,925)	8,017
Other assets, net	(6,126)	(1,434)	739
Net cash provided by (used in) investing activities	(1,862)	(883,180)	(302,049)
Cash flows from financing activities
Dividends and dividend equivalents paid	(103,298)	(97,458)	(2,061)
Issuance of common stock	1,382	1,553	2,416
Repurchases of common stock	(399,100)	(226,305)	(300,201)
Issuance of senior notes, net	0	515,567	442,439
Repayments and repurchases of senior notes	0	0	(610,763)
Credit facility commitment fees paid	(3,325)	(2,292)	(989)
Change in secured borrowings	1,057	0	0
Net cash provided by (used in) financing activities	(496,776)	222,618	(403,106)
Effect of exchange rate changes on cash and restricted cash	0	0	(4)
Increase (decrease) in cash and restricted cash	58,474	(2,128)	(10,728)
Cash and restricted cash, beginning of period	94,146	96,274	107,002
Cash and restricted cash, end of period	152,620	94,146	96,274
Parent Company
Cash flows from operating activities
Net cash provided by (used in) operating activities	66,317	(13,741)	143,664
Cash flows from investing activities
Fixed-maturities available for sale	195,452	304,737	296,171
Trading securities	0	0	56,787
Equity securities	0	13,401	16,916
Fixed-maturities available for sale	301,788	238,161	149,767
Trading securities	0	0	114
Fixed-maturities available for sale	156,344	691,874	293,284
Short-term investments, net	113,939	(53,024)	157,045
Other assets, net	(864)	(6,068)	(6,958)
Capital distributions from subsidiaries	44,951	19,000	6,000
Capital contributions to subsidiaries	(43,250)	(5,050)	(65,879)
Net cash provided by (used in) investing activities	455,672	(180,717)	316,679
Cash flows from financing activities
Dividends and dividend equivalents paid	(103,298)	(97,458)	(2,061)
Issuance of common stock	1,382	1,553	2,416
Repurchases of common stock	(399,100)	(226,305)	(300,201)
Issuance of senior notes, net	0	515,567	442,439
Repayments and repurchases of senior notes	0	0	(610,763)
Credit facility commitment fees paid	(3,325)	(2,292)	(989)
Net cash provided by (used in) financing activities	(503,284)	191,065	(469,159)
Effect of exchange rate changes on cash and restricted cash	0	0	(2)
Increase (decrease) in cash and restricted cash	18,705	(3,393)	(8,818)
Cash and restricted cash, beginning of period	20,141	23,534	32,352
Cash and restricted cash, end of period	38,846	20,141	23,534
Cash distributions received from consolidated subsidiaries	85,000	1,700	26,600
Dividends received from consolidated subsidiaries	$ 92,300	$ 484,100	$ 362,400