Consolidated Statements Of Operations And Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
REVENUES:
Premiums earned	$ 1,494,005	$ 1,270,454
Net investment income	74,201	84,534
Net realized capital gains (losses):
Credit allowances on fixed maturity securities	(12,099)
Other-than-temporary impairments on fixed maturity securities		(2,290)
Other net realized capital gains (losses)	268,966	137,346
Total net realized capital gains (losses)	256,867	135,056
Other income (expense)	(4,498)	(730)
Total revenues	1,820,575	1,489,314
CLAIMS AND EXPENSES:
Incurred losses and loss adjustment expenses	1,029,513	796,096
Commission, brokerage, taxes and fees	323,104	288,218
Other underwriting expenses	101,208	78,382
Corporate expenses	3,721	1,651
Interest, fee and bond issue cost amortization expense	7,460	9,828
Total claims and expenses	1,465,006	1,174,175
INCOME (LOSS) BEFORE TAXES	355,569	315,139
Income tax expense (benefit)	38,924	63,531
NET INCOME (LOSS)	316,645	251,608
Other comprehensive income (loss), net of tax :
Unrealized appreciation (depreciation) ("URA(D)") on securities arising during the period	(177,524)	88,449
Less: reclassification adjustment for realized losses (gains) included in net income (loss)	27,886	(1,016)
Total URA(D) on securities arising during the period	(149,638)	87,433
Foreign currency translation adjustments	(29,633)	9,564
Reclassification adjustment for amortization of net (gain) loss included in net income (loss)	920	1,151
Total benefit plan net gain (loss) for the period	920	1,151
Total other comprehensive income (loss), net of tax	(178,351)	98,148
COMPREHENSIVE INCOME (LOSS)	$ 138,294	$ 349,756