Consolidated Statements Of Operations And Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
REVENUES:
Premiums earned	$ 1,218,867	$ 1,272,488
Net investment income	102,524	122,566
Net realized capital gains (losses):
Other-than-temporary impairments on fixed maturity securities	$ (28,793)	$ (26,018)
Other-than-temporary impairments on fixed maturity securities transferred to other comprehensive income (loss)
Other net realized capital gains (losses)	$ (45,466)	$ 15,513
Total net realized capital gains (losses)	(74,259)	(10,505)
Net derivative gain (loss)	(3,020)	(242)
Other income (expense)	(2,066)	51,281
Total revenues	1,242,046	1,435,588
CLAIMS AND EXPENSES:
Incurred losses and loss adjustment expenses	700,749	715,155
Commission, brokerage, taxes and fees	275,006	283,094
Other underwriting expenses	72,110	58,741
Corporate expenses	7,886	5,463
Interest, fees and bond issue cost amortization expense	9,228	8,990
Total claims and expenses	1,064,979	1,071,443
INCOME (LOSS) BEFORE TAXES	177,067	364,145
Income tax expense (benefit)	5,381	41,167
NET INCOME (LOSS)	171,686	322,978
Other comprehensive income (loss), net of tax :
Unrealized appreciation (depreciation) ("URA(D)") on securities arising during the period	142,962	83,205
Reclassification adjustment for realized losses (gains) included in net income (loss)	32,381	22,183
Total URA(D) on securities arising during the period	175,343	105,388
Foreign currency translation adjustments	$ 9,773	$ (102,340)
Benefit plan actuarial net gain (loss) for the period
Reclassification adjustment for amortization of net (gain) loss included in net income (loss)	$ 1,340	$ 1,604
Total benefit plan net gain (loss) for the period	1,340	1,604
Total other comprehensive income (loss), net of tax	186,456	4,652
COMPREHENSIVE INCOME (LOSS)	$ 358,142	$ 327,630
EARNINGS PER COMMON SHARE:
Basic	$ 4.03	$ 7.26
Diluted	4.00	7.19
Dividends declared	$ 1.15	$ 0.95