Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ 412,653	$ 454,126	$ 798,263
Adjustments to reconcile net income to net cash provided by operating activities:
Decrease (increase) in premiums receivable	(49,602)	83,362	(175,854)
Decrease (increase) in funds held by reinsureds, net	4,737	2,236	(12,075)
Decrease (increase) in reinsurance receivables	(465,761)	(460,635)	25,665
Decrease (increase) in income taxes	57,487	68,206	351,573
Decrease (increase) in prepaid reinsurance premiums	30,985	(138,010)	(118,173)
Increase (decrease) in reserve for losses and loss adjustment expenses	184,845	248,053	(439,560)
Increase (decrease) in unearned premiums	(82,494)	130,519	228,097
Increase (decrease) in other net payable to reinsurers	204,526	5,130	127,252
Increase (decrease) in losses in course of payment	(51,416)	(171,071)	171,829
Change in equity adjustments in limited partnerships	(18,144)	(28,249)	(35,721)
Distribution of limited partnership income	45,235	41,064	24,133
Change in other assets and liabilities, net	7,499	81,388	25,049
Non-cash compensation expense	8,025	7,911	7,983
Amortization of bond premium (accrual of bond discount)	18,160	19,086	25,599
Amortization of underwriting discount on senior notes	4	46	54
Net realized capital (gains) losses	(50,335)	(206,679)	(723,149)
Net cash provided by (used in) operating activities	256,404	136,483	280,965
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from fixed maturities matured/called - available for sale, at market value	902,932	1,071,296	1,099,850
Proceeds from fixed maturities matured/called - available for sale, at fair value		875	7,213
Proceeds from fixed maturities sold - available for sale, at market value	544,955	1,080,276	598,342
Proceeds from fixed maturities sold - available for sale, at fair value	1,824	36,467	21,572
Proceeds from equity securities sold - available for sale, at market value	16
Proceeds from equity securities sold - available for sale, at fair value	567,069	528,958	612,516
Proceeds from sale of subsidiary (net of cash disposed)	3,934
Distributions from other invested assets	51,494	72,323	64,483
Cost of fixed maturities acquired - available for sale, at market value	(1,811,463)	(2,406,162)	(1,611,791)
Cost of fixed maturities acquired - available for sale, at fair value	(2,436)	(24,097)	(6,196)
Cost of equity securities acquired - available for sale, at fair value	(530,538)	(416,375)	(439,115)
Cost of other invested assets acquired	(93,728)	(134,373)	(17,926)
Net change in short-term investments	(6,145)	189,139	(292,751)
Net cost of lending for long term note - affiliated		(250,000)
Net change in unsettled securities transactions	(23,447)	(4,157)	(3,057)
Net cash provided by (used in) investing activities	(395,533)	(255,830)	33,140
CASH FLOWS FROM FINANCING ACTIVITIES:
Tax benefit from share-based compensation	4,472	3,331	2,845
Net cost of junior subordinated debt securities redemption			(329,897)
Net proceeds from issuance of senior notes		400,000
Net cost of senior notes maturing		(250,000)
Net cash provided by (used in) financing activities	4,472	153,331	(327,052)
EFFECT OF EXCHANGE RATE CHANGES ON CASH	(33,889)	(26,816)	(17,966)
Net increase (decrease) in cash	(168,546)	7,168	(30,913)
Cash, beginning of period	323,975	316,807	347,720
Cash, end of period	155,429	323,975	316,807
SUPPLEMENTAL CASH FLOW INFORMATION:
Income taxes paid (recovered)	131,632	133,057	51,045
Interest paid	35,217	$ 38,861	$ 37,725
Non-cash transaction:
Exchange of common shares of parent company, held as other invested assets at fair value, for preferred shares of an affiliated company, held as other invested assets at fair value	$ 1,773,214