Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Investments and cash:
Fixed maturities, available-for-sale, at fair value (amortized cost: 2013, $2,001,865; 2012, $2,034,765)	$ 2,078,003	$ 2,121,833
Equity securities, available-for-sale, at fair value (cost: 2013, $92,017; 2012, $85,004)	116,482	101,297
Short-term investments, at cost which approximates fair value	129,475	153,788
Cash	58,576	45,336
Total investments and cash	2,382,536	2,422,254
Premiums receivable	400,397	320,182
Prepaid reinsurance premiums	232,776	221,015
Reinsurance recoverable on paid losses	51,955	49,282
Reinsurance recoverable on unpaid losses and loss adjustment expenses	872,290	880,139
Deferred policy acquisition costs	69,349	61,005
Accrued investment income	13,640	12,587
Goodwill and other intangible assets	6,785	7,093
Deferred income tax, net	4,049	3,216
Receivable for investments sold	9,334	4,310
Other assets	27,934	26,587
Total assets	4,071,045	4,007,670
Liabilities:
Reserves for losses and loss adjustment expenses	2,104,386	2,097,048
Unearned premiums	719,383	642,407
Reinsurance balances payable	165,113	165,813
Senior Notes	114,462	114,424
Current income tax payable, net	7,078	2,133
Payable for investments purchased	20,905	58,345
Accounts payable and other liabilities	42,960	48,015
Total liabilities	3,174,287	3,128,185
Stockholders' equity:
Preferred stock, $.10 par value, authorized 1,000,000 shares, none issued
Common stock, $.10 par value, authorized 50,000,000 shares, issued 17,641,357 shares for 2013 and 17,558,046 shares for 2012	1,763	1,755
Additional paid-in capital	331,932	329,452
Treasury stock, at cost (3,511,380 shares for 2013 and 2012)	(155,801)	(155,801)
Retained earnings	642,781	628,871
Accumulated other comprehensive income	76,083	75,208
Total stockholders' equity	896,758	879,485
Total liabilities and stockholders' equity	$ 4,071,045	$ 4,007,670