Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
REVENUES:
Net premiums written	$ 10,004,070	$ 8,862,867	$ 7,262,437
Change in net unearned premiums	(442,641)	(756,836)	(331,594)
Net premiums earned	9,561,429	8,106,031	6,930,843
Net investment income	779,185	671,618	583,821
Net investment gains:
Unrealized investment gains (losses), before tax	217,311	106,958	73,514
Change in allowance for expected credit losses on investments	(14,914)	(16,326)	29,486
Net investment gains	202,397	90,632	103,000
Revenues from non-insurance businesses	509,548	489,151	389,888
Insurance service fees	110,544	93,857	88,777
Other income	3,396	4,177	2,596
Total revenues	11,166,499	9,455,466	8,098,925
OPERATING COSTS AND EXPENSES:
Losses and loss expenses	5,861,750	4,953,960	4,468,706
Other operating costs and expenses	2,961,505	2,599,270	2,390,392
Expenses from non-insurance businesses	493,189	472,151	384,488
Interest expense	130,374	147,180	150,537
Total operating costs and expenses	9,446,818	8,172,561	7,394,123
Pre-Tax Income (Loss)	1,719,681	1,282,905	704,802
Income tax expense	(334,727)	(251,890)	(171,817)
Net income before noncontrolling interests	1,384,954	1,031,015	532,985
Noncontrolling interests	(3,892)	(8,525)	(2,315)
Net income to common stockholders	$ 1,381,062	$ 1,022,490	$ 530,670
NET INCOME PER SHARE:
Basic (dollars per share)	$ 4.99	$ 3.69	$ 1.89
Diluted (dollars per share)	$ 4.94	$ 3.66	$ 1.87