Consolidated Statements Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
REVENUES:
Net premiums written	$ 2,212,181	$ 1,739,818	$ 4,262,219	$ 3,585,664
Change in net unearned premiums	(240,557)	(62,903)	(440,639)	(217,331)
Net premiums earned	1,971,624	1,676,915	3,821,580	3,368,333
Net investment income	168,187	85,431	326,764	260,194
Net realized and unrealized gains (losses) on investments	20,461	61,653	72,219	(81,632)
Change in allowance for expected credit losses on investments	3,603	16,232	(13,316)	(17,657)
Net investment gains (losses)	24,064	77,885	58,903	(99,289)
Revenues from non-insurance businesses	109,122	75,742	196,552	169,471
Insurance service fees	22,256	19,870	48,064	45,621
Other income	833	183	1,092	2,305
Total revenues	2,296,086	1,936,026	4,452,955	3,746,635
OPERATING COSTS AND EXPENSES:
Losses and loss expenses	1,203,647	1,135,126	2,325,238	2,242,379
Other operating costs and expenses	647,705	580,840	1,263,973	1,159,173
Expenses from non-insurance businesses	106,698	76,238	192,989	170,996
Interest expense	38,096	38,373	74,747	75,105
Total operating costs and expenses	1,996,146	1,830,577	3,856,947	3,647,653
Income before income taxes	299,940	105,449	596,008	98,982
Income tax expense	(62,262)	(33,793)	(126,614)	(30,852)
Net income before noncontrolling interests	237,678	71,656	469,394	68,130
Noncontrolling interests	(440)	(396)	(2,631)	(1,288)
Net income to common stockholders	$ 237,238	$ 71,260	$ 466,763	$ 66,842
NET INCOME PER SHARE:
Basic (in dollar per share)	$ 1.28	$ 0.38	$ 2.52	$ 0.36
Diluted (in dollar per share)	$ 1.27	$ 0.38	$ 2.50	$ 0.35