Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 247,937	$ 374,607	$ 320,087
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	79,056	68,463	64,730
Net realized investment gains	(111,658)	(85,731)	(222,793)
(Increase) decrease in premiums receivable	(26,670)	13,946	(49,832)
Decrease in reinsurance recoverables	3,488	30,127	142,314
Changes in current and deferred income taxes	(18,097)	31,236	72,545
Increase in deferred policy acquisition costs	(11,265)	(13,828)	(18,035)
Increase in loss and loss adjustment expense reserves	235,126	70,049	91,843
Increase in unearned premiums	113,926	50,326	119,366
(Decrease) increase in accounts payable and accrued expenses	(26,724)	51,988	26,493
Share-based compensation	141	142	123
Other, net	16,324	14,291	(27,163)
Net cash provided by operating activities	501,584	605,616	519,678
Fixed maturity securities available for sale in nature:
Purchases	(1,460,641)	(878,213)	(491,795)
Sales	336,201	168,087	136,560
Calls or maturities	518,557	250,878	316,860
Equity securities available for sale in nature
Purchases	(958,008)	(1,230,785)	(1,174,759)
Sales	943,857	1,174,540	1,088,701
Calls	0	3,880	0
Changes in securities payable and receivable	8,327	873	(2,536)
Decrease (increase) in short-term investments	270,383	118,830	(240,391)
Purchase of fixed assets	(41,442)	(39,953)	(40,088)
Other, net	9,096	20,577	6,247
Net cash used in investing activities	(373,670)	(411,286)	(401,201)
CASH FLOWS FROM FINANCING ACTIVITIES
Dividends paid to shareholders	(140,226)	(139,640)	(139,071)
Proceeds from stock options exercised	215	0	701
Payments on finance lease obligations	(825)	(609)	0
Net cash used in financing activities	(140,836)	(140,249)	(138,370)
Net (decrease) increase in cash	(12,922)	54,081	(19,893)
Cash:
Beginning of year	348,479	294,398	314,291
End of year	335,557	348,479	294,398
SUPPLEMENTAL CASH FLOW DISCLOSURE
Interest paid	16,616	16,599	16,586
Income taxes paid (refunded), net	$ 69,467	$ 52,659	$ (14,564)