Unaudited Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Operating Activities
Net income	$ 473,134	$ 424,984
Adjustments to reconcile net income to net cash provided by operating activities:
Net realized (gains) losses	(74,985)	(126,337)
Net impairment losses recognized in earnings	3,537	12,982
Equity in net income or loss of investment funds accounted for using the equity method and other income or loss	(47,529)	11,161
Amortization of intangible assets	62,118	9,628
Share-based compensation	42,739	35,769
Changes in:
Reserve for losses and loss adjustment expenses, net of unpaid losses and loss adjustment expenses recoverable	180,342	186,199
Unearned premiums, net of ceded unearned premiums	167,064	187,234
Premiums receivable	(222,498)	(278,814)
Deferred acquisition costs	(53,553)	(33,450)
Reinsurance balances payable	50,112	73,712
Other items, net	(26,414)	38,156
Net Cash Provided By Operating Activities	554,067	541,224
Investing Activities
Purchases of fixed maturity investments	(19,899,326)	(17,541,731)
Purchases of equity securities	(400,155)	(212,678)
Purchases of other investments	(883,704)	(650,613)
Proceeds from sales of fixed maturity investments	19,611,680	16,978,549
Proceeds from sales of equity securities	473,064	337,619
Proceeds from sales, redemptions and maturities of other investments	614,494	636,535
Proceeds from redemptions and maturities of fixed maturity investments	447,941	370,980
Net settlements of derivative instruments	(5,984)	45,174
Net (purchases) sales of short-term investments	(445,203)	(304,460)
Change in cash collateral related to securities lending	175,693	(18,715)
Acquisitions, net of cash	0	(1,460)
Purchases of fixed assets	(11,103)	(8,284)
Other	(13,792)	13,416
Net Cash Provided By (Used For) Investing Activities	(336,395)	(355,668)
Financing Activities
Purchases of common shares under share repurchase program	0	(75,256)
Proceeds from common shares issued, net	(6,838)	(1,487)
Proceeds from borrowings	0	46,000
Repayments of borrowings	(72,000)	(179,171)
Change in cash collateral related to securities lending	(175,693)	18,715
Dividends paid to redeemable noncontrolling interests	(8,994)	(8,994)
Other	(41,698)	(2,223)
Preferred dividends paid	(22,567)	(10,969)
Net Cash Provided By (Used For) Financing Activities	(327,790)	(213,385)
Effects of exchange rate changes on foreign currency cash	7,496	(8,906)
Increase (decrease) in cash	(102,622)	(36,735)
Cash beginning of year	842,942	553,326
Cash end of period	740,320	516,591
Income taxes paid	3,935	26,619
Interest paid	$ 58,035	$ 31,524