Consolidated Statements Of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues:
Net premiums earned	$ 888,776	$ 833,959	$ 1,759,021	$ 1,642,043
Net investment income	35,032	34,786	69,206	66,296
Net realized investment gains (losses)	53,329	14,290	164,403	(44,445)
Other	2,350	2,356	4,600	4,681
Total revenues	979,487	885,391	1,997,230	1,668,575
Expenses:
Losses and loss adjustment expenses	656,577	605,547	1,286,993	1,237,781
Policy acquisition costs	148,629	141,520	297,042	282,504
Other operating expenses	68,420	60,822	135,909	126,221
Interest	4,266	4,256	8,522	8,522
Total expenses	877,892	812,145	1,728,466	1,655,028
Income before income taxes	101,595	73,246	268,764	13,547
Income tax expense (benefit)	18,345	13,066	49,647	(4,026)
Net income	$ 83,250	$ 60,180	$ 219,117	$ 17,573
Net income per share:
Basic (in dollars per share)	$ 1.50	$ 1.09	$ 3.96	$ 0.32
Diluted (in dollars per share)	$ 1.50	$ 1.09	$ 3.96	$ 0.32
Weighted average shares outstanding:
Basic (in shares)	55,353	55,332	55,347	55,332
Diluted (in shares)	55,363	55,335	55,356	55,335