Consolidated Statements Of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenues:
Net premiums earned	$ 811,898	$ 888,776	$ 1,734,471	$ 1,759,021
Net investment income	34,166	35,032	68,661	69,206
Net realized investment gains (losses)	158,426	53,329	(92,894)	164,403
Other	1,353	2,350	3,915	4,600
Total revenues	1,005,843	979,487	1,714,153	1,997,230
Expenses:
Losses and loss adjustment expenses	495,300	656,577	1,146,970	1,286,993
Policy acquisition costs	149,706	148,629	306,240	297,042
Other operating expenses	71,103	68,420	147,660	135,909
Interest	4,268	4,266	8,523	8,522
Total expenses	720,377	877,892	1,609,393	1,728,466
Income before income taxes	285,466	101,595	104,760	268,764
Income tax expense	57,255	18,345	15,753	49,647
Net income	$ 228,211	$ 83,250	$ 89,007	$ 219,117
Net income per share:
Basic (in dollars per share)	$ 4.12	$ 1.50	$ 1.61	$ 3.96
Diluted (in dollars per share)	$ 4.12	$ 1.50	$ 1.61	$ 3.96
Weighted average shares outstanding:
Basic (in shares)	55,358	55,353	55,358	55,347
Diluted (in shares)	55,358	55,363	55,358	55,356