Condensed Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Earnings (loss) before equity in net earnings of subsidiaries	$ 191,642,000	$ 64,179,000	$ 105,028,000
Adjustments to reconcile net earnings to net cash provided by operating activities
Net realized gains	(17,520,000)	(63,407,000)	(4,411,000)
Net unrealized (gains) losses on equity securities	(78,090,000)	98,735,000
Depreciation	8,164,000	7,042,000	6,944,000
Deferred income tax expense (benefit)	14,666,000	(20,515,000)	(29,741,000)
Other items, net	25,341,000	6,171,000	16,368,000
Change in:
Accrued investment income	(552,000)	1,132,000	(573,000)
Premiums and reinsurance balances receivable (net of direct write-offs and commutations)	(7,793,000)	(18,225,000)	(7,964,000)
Reinsurance balances payable	3,100,000	967,000	3,696,000
Funds held	11,049,000	(2,251,000)	1,818,000
Ceded unearned premium	(22,482,000)	(13,246,000)	(5,755,000)
Reinsurance balances recoverable on unpaid losses	(19,518,000)	(63,008,000)	(13,767,000)
Deferred policy acquisition costs	(110,000)	(7,218,000)	(4,569,000)
Accrued expenses	21,502,000	(7,724,000)	856,000
Unpaid losses and settlement expenses	113,004,000	189,845,000	132,166,000
Unearned premiums	43,708,000	45,056,000	17,672,000
Current income taxes payable	(1,434,000)	5,725,000	(3,019,000)
Changes in investment in unconsolidated investees:
Undistributed earnings	(20,960,000)	(16,056,000)	(17,224,000)
Dividends received	13,200,000	9,900,000	0
Net Cash Provided by (Used in) Operating Activities, Total	276,917,000	217,102,000	197,525,000
Purchase of:
Fixed income, available-for-sale	(539,726,000)	(725,675,000)	(430,727,000)
Equity securities	(89,486,000)	(115,921,000)	(20,719,000)
Property and equipment	(6,955,000)	(6,087,000)	(9,238,000)
Other	(22,751,000)	(18,754,000)	(19,112,000)
Proceeds from sale of:
Fixed income, available-for-sale	196,558,000	395,019,000	168,760,000
Proceeds from sale of equity securities	62,172,000	147,838,000	36,573,000
Property and equipment		167,000	128,000
Subsidiary or agency			408,000
Other	2,502,000	3,394,000	2,063,000
Proceeds from call or maturity of:
Fixed income, available-for-sale	201,383,000	187,380,000	195,617,000
Payments for (Proceeds from) Short-term Investments
Net proceeds from sale (purchase) of short-term investments	11,550,000	(1,570,000)	(4,965,000)
Net cash used in investing activities	(184,753,000)	(134,209,000)	(81,212,000)
Cash Flows from Financing Activities
Proceeds from stock option exercises	9,490,000	6,076,000	3,502,000
Cash dividends paid	(85,591,000)	(83,100,000)	(113,813,000)
Net cash used in financing activities	(76,101,000)	(77,024,000)	(110,311,000)
Net increase (decrease) in cash	16,063,000	5,869,000	6,002,000
Cash at the beginning of the period	30,140,000	24,271,000	18,269,000
Cash at the end of the period	$ 46,203,000	$ 30,140,000	$ 24,271,000