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	$ 107,150	$ 1,068,113	$ 673,442
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of net premium on investments	93,754	107,047	151,666
Amortization of intangible assets	26,593	27,486	27,180
Net realized and unrealized investment losses (gains)	297,479	(371,796)	160,735
Changes in:
Reinsurance balances, net	(122,866)	(142,268)	(507,346)
Reinsurance recoverable on paid and unpaid losses, net of ceded premiums payable	55,172	46,857	45,422
Funds held by reinsured companies and funds held – directly managed	131,713	188,902	99,394
Deferred acquisition costs	(5,784)	(55,786)	(72,956)
Net tax assets and liabilities	(105,635)	(10,951)	(99,067)
Unpaid losses and loss expenses including life policy benefits	(118,976)	(168,490)	41,956
Unearned premiums	(39,630)	110,689	198,316
Other net changes in operating assets and liabilities	(158)	52,796	108,525
Net cash provided by operating activities	318,812	852,599	827,267
Cash flows from investing activities
Redemptions of fixed maturities	743,743	696,301	1,167,483
Sales and redemptions of short-term investments	178,166	92,956	312,376
Purchases of short-term investments	(200,533)	(106,364)	(176,339)
Other, net	(151,198)	(58,840)	(786)
Net cash provided by (used in) investing activities	295,274	(250,007)	417,993
Cash flows from financing activities
Dividends paid to common and preferred shareholders	(190,339)	(190,960)	(200,078)
Repurchase of common shares	(71,376)	(547,120)	(715,421)
Reissuance of treasury shares and issuance of common shares, net of taxes paid	7,996	16,785	51,111
(Distribution) sale of shares to noncontrolling interests	(55,820)	(14,265)	47,193
Net proceeds from issuance of preferred shares	0	0	241,265
Repurchase of preferred shares	0	0	(290,000)
Net cash used in financing activities	(309,539)	(735,560)	(865,930)
Effect of foreign exchange rate changes on cash	(40,918)	(50,049)	(4,550)
Increase (decrease) in cash and cash equivalents	263,629	(183,017)	374,780
Cash and cash equivalents—beginning of year	1,313,468	1,496,485	1,121,705
Cash and cash equivalents—end of year	1,577,097	1,313,468	1,496,485
Supplemental cash flow information:
Taxes paid	220,336	284,798	174,031
Interest paid	49,259	49,259	49,259
Fixed maturities
Sales of fixed maturities and sales of equities	7,796,537	8,730,831	7,887,186
Purchases of fixed maturities and purchases of equities	(8,608,288)	(9,844,660)	(8,872,874)
Equities
Sales of fixed maturities and sales of equities	1,184,380	691,970	796,403
Purchases of fixed maturities and purchases of equities	$ (647,533)	$ (452,201)	$ (695,456)