Condensed Consolidated Statements of Earnings and Comprehensive Earnings (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Net premiums earned	$ 137,280	$ 116,051
Net investment income	15,293	16,303
Net realized investment gains	11,416	4,472
Other-than-temporary impairment (OTTI) losses on investments	0	0
Consolidated revenue	163,989	136,826
Losses and settlement expenses	61,883	46,871
Policy acquisition costs	48,197	38,618
Insurance operating expenses	12,259	9,615
Interest expense on debt	1,500	1,512
General corporate expenses	1,987	2,005
Total expenses	125,826	98,621
Equity in earnings of unconsolidated investee	2,946	2,616
Earnings before income taxes	41,109	40,821
Income tax expense	13,071	13,115
Net earnings	28,038	27,706
Unrealized gains (losses) on securities:
Unrealized holding gains arising during the period	19,509	8,154
Less: Reclassification adjustment for (gains) included in net earnings	(8,733)	(2,906)
Other comprehensive earnings	10,776	5,248
Comprehensive earnings	$ 38,814	$ 32,954
Basic:
Basic net earnings per share (in dollars per share)	$ 1.32	$ 1.32
Basic comprehensive earnings per share (in dollars per share)	$ 1.83	$ 1.57
Diluted:
Diluted net earnings per share (in dollars per share)	$ 1.30	$ 1.30
Diluted comprehensive earnings per share (in dollars per share)	$ 1.80	$ 1.55
Weighted average number of common shares outstanding
Basic (in shares)	21,188	21,025
Diluted (in shares)	21,528	21,285
Cash dividends declared per common share (in dollars per share)	$ 0.30	$ 0.29