Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
REVENUES:
Net premiums written	$ 6,433,227	$ 6,260,508	$ 6,423,913
Change in net unearned premiums	(61,722)	50,911	(130,565)
Net premiums earned	6,371,505	6,311,419	6,293,348
Net investment income	674,235	575,788	564,163
Net realized and unrealized gains on investments:
Net realized and unrealized gains before OTTI	160,175	335,858	285,119
Other-than-temporary impairments (OTTI)	(5,687)	0	(18,114)
Net realized and unrealized gains on investments	154,488	335,858	267,005
Revenues from non-insurance businesses	372,985	326,165	390,348
Insurance service fees	117,757	134,729	138,944
Other income	681	805	376
Total revenues	7,691,651	7,684,764	7,654,184
OPERATING COSTS AND EXPENSES:
Losses and loss expenses	3,974,702	4,002,348	3,845,800
Other operating costs and expenses	2,383,221	2,436,932	2,395,619
Expenses from non-insurance businesses	364,449	325,417	375,431
Interest expense	157,185	147,297	140,896
Total operating costs and expenses	6,879,557	6,911,994	6,757,746
Income before income taxes	812,094	772,770	896,438
Income tax expense	(163,028)	(219,433)	(292,953)
Net income before noncontrolling interests	649,066	553,337	603,485
Noncontrolling interests	(8,317)	(4,243)	(1,569)
Net income to common stockholders	$ 640,749	$ 549,094	$ 601,916
NET INCOME PER SHARE:
Basic (dollars per share)	$ 5.06	$ 4.40	$ 4.91
Diluted (dollars per share)	$ 5.00	$ 4.26	$ 4.68