Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ 249,710	$ 244,640
Adjustments to reconcile net income to net cash provided by operating activities:
Decrease (increase) in premiums receivable	(19,661)	(82,537)
Decrease (increase) in funds held by reinsureds, net	(1,191)	401
Decrease (increase) in reinsurance receivables	(167,876)	(368,394)
Decrease (increase) in income taxes	34,836	36,879
Decrease (increase) in prepaid reinsurance premiums	38,141	(100,075)
Increase (decrease) in reserve for losses and loss adjustment expenses	75,995	7,882
Increase (decrease) in unearned premiums	(99,896)	101,264
Increase (decrease) in other net payable to reinsurers	(144,661)	83,206
Increase (decrease) in losses in course of payment	76,607	151,503
Change in equity adjustments in limited partnerships	(13,872)	1,161
Distribution of limited partnership income	14,597	9,157
Change in other assets and liabilities, net	2,437	(51,901)
Non-cash compensation expense	3,955	3,698
Amortization of bond premium (accrual of bond discount)	9,352	11,581
Amortization of underwriting discount on senior notes	2	28
Net realized capital (gains) losses	(72,521)	(121,064)
Net cash provided by (used in) operating activities	(14,046)	(72,571)
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from fixed maturities matured/called - available for sale, at market value	493,648	519,733
Proceeds from fixed maturities matured/called - available for sale, at fair value		875
Proceeds from fixed maturities sold - available for sale, at market value	288,211	327,859
Proceeds from fixed maturities sold - available for sale, at fair value	1,613	20,763
Proceeds from equity securities sold - available for sale, at market value	16
Proceeds from equity securities sold - available for sale, at fair value	303,477	292,943
Distributions from other invested assets	19,999	15,271
Cost of fixed maturities acquired - available for sale, at market value	(850,526)	(1,499,373)
Cost of fixed maturities acquired - available for sale, at fair value	(234)	(1,309)
Cost of equity securities acquired - available for sale, at fair value	(306,602)	(163,452)
Cost of other invested assets acquired	(33,996)	(32,764)
Net change in short-term investments	30,157	83,935
Net change in unsettled securities transactions	3,008	6,953
Net cash provided by (used in) investing activities	(51,229)	(428,566)
CASH FLOWS FROM FINANCING ACTIVITIES:
Tax benefit from share-based compensation	3,036	2,788
Proceeds from issuance of senior notes		400,000
Net cash provided by (used in) financing activities	3,036	402,788
EFFECT OF EXCHANGE RATE CHANGES ON CASH	(11,317)	8,575
Net increase (decrease) in cash	(73,556)	(89,774)
Cash, beginning of period	323,975	316,807
Cash, end of period	250,419	227,033
SUPPLEMENTAL CASH FLOW INFORMATION:
Income taxes paid (recovered)	77,577	84,406
Interest paid	$ 17,608	$ 14,719