Consolidated Statements Of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Revenues:
Net premiums earned	$ 705,237	$ 678,913	$ 2,086,827	$ 2,017,295
Net investment income	32,564	30,857	93,656	93,706
Net realized investment (losses) gains	(20,089)	16,212	102,813	(7,153)
Other	2,275	2,685	6,666	7,539
Total revenues	719,987	728,667	2,289,962	2,111,387
Expenses:
Losses and loss adjustment expenses	492,525	492,558	1,452,171	1,446,524
Policy acquisition costs	131,090	126,891	393,964	377,006
Other operating expenses	58,545	54,087	166,341	166,165
Interest	707	338	1,900	864
Total expenses	682,867	673,874	2,014,376	1,990,559
Income before income taxes	37,120	54,793	275,586	120,828
Income tax expense	5,824	15,223	76,681	24,061
Net income	$ 31,296	$ 39,570	$ 198,905	$ 96,767
Net income per share:
Basic (in dollars per share)	$ 0.57	$ 0.72	$ 3.62	$ 1.76
Diluted (in dollars per share)	$ 0.57	$ 0.72	$ 3.62	$ 1.76
Weighted average shares outstanding:
Basic (in shares)	55,002	54,959	54,986	54,941
Diluted (in shares)	55,014	54,973	54,995	54,957
Dividends paid per share (in dollars per share)	$ 0.6150	$ 0.6125	$ 1.845	$ 1.8375