Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 73,044	$ 74,479	$ 177,949
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	26,385	26,478	28,054
Net realized investment losses (gains)	34,255	83,807	(81,184)
Bond amortization, net	26,873	21,360	18,918
Excess tax benefits related to share-based compensation	(913)	(27)	(148)
Increase in premiums receivable	(22,531)	(41,512)	(23,934)
Changes in current and deferred income taxes	(2,130)	(35,287)	8,343
Decrease (increase) in deferred policy acquisition costs	936	(4,560)	(2,736)
Increase in unpaid losses and loss adjustment expenses	143,560	36,214	52,813
Increase in unearned premiums	25,124	42,552	46,271
(Decrease) increase in accounts payable and accrued expenses	(10,586)	(35,086)	31,019
Share-based compensation	142	5,208	4,112
(Decrease) increase in other payables	(2,627)	18,114	(10,988)
Other, net	(4,059)	(1,496)	(1,954)
Net cash provided by operating activities	287,473	190,244	246,535
CASH FLOWS FROM INVESTING ACTIVITIES
Fixed maturity securities available-for-sale in nature: Purchases	(1,077,638)	(965,701)	(542,494)
Fixed maturity securities available-for-sale in nature: Sales	396,766	260,946	209,680
Fixed maturity securities available-for-sale in nature: Calls or maturities	647,059	386,644	330,637
Equity securities available for sale in nature:
Purchases	(714,113)	(748,217)	(868,383)
Sales	696,138	805,417	745,058
Calls	0	2,851	1,044
Changes in securities payable and receivable	29,958	(1,387)	9,294
Net (increase) decrease in short-term investments and purchased options	(191,530)	187,492	(56,530)
Purchase of fixed assets	(16,979)	(20,112)	(26,037)
Sale of fixed assets	14	141	224
Business acquisition, net of cash acquired	0	7,771	0
Other, net	3,605	2,473	3,472
Net cash used in investing activities	(226,720)	(81,682)	(194,035)
CASH FLOWS FROM FINANCING ACTIVITIES
Dividends paid to shareholders	(137,201)	(136,386)	(135,496)
Excess tax benefits related to share-based compensation	913	27	148
Proceeds from stock options exercised	1,632	2,111	6,247
Proceeds from bank loan	30,000	0	100,000
Net cash used in financing activities	(104,656)	(134,248)	(29,101)
Net (decrease) increase in cash	(43,903)	(25,686)	23,399
Cash:
Beginning of year	264,221	289,907	266,508
End of year	220,318	264,221	289,907
SUPPLEMENTAL CASH FLOW DISCLOSURE
Interest paid	3,531	2,989	2,543
Income taxes (refunded)	$ (183)
Income taxes paid		$ 31,390	$ 61,139