Unaudited Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating Activities
Net income (loss)	$ 197,432	$ 475,708
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Net realized (gains) losses	289,213	(161,007)
Equity in net (income) or loss of investment funds accounted for using the equity method and other income or loss	(11,420)	(135,939)
Amortization of intangible assets	27,167	14,402
Share-based compensation	45,379	40,812
Changes in:
Reserve for losses and loss adjustment expenses, net of unpaid losses and loss adjustment expenses recoverable	275,954	560,153
Unearned premiums, net of ceded unearned premiums	513,507	560,035
Premiums receivable	(600,691)	(608,250)
Deferred acquisition costs	(96,999)	(126,701)
Reinsurance balances payable	(74,022)	240,206
Other items, net	(13,957)	(96,574)
Net cash provided by (used for) operating activities	551,563	762,845
Investing Activities
Purchases of fixed maturity investments	(6,727,665)	(11,530,968)
Purchases of equity securities	(408,615)	(309,419)
Purchases of other investments	(616,659)	(430,961)
Proceeds from sales of fixed maturity investments	6,053,352	10,917,134
Proceeds from sales of equity securities	1,100,256	284,986
Proceeds from sales, redemptions and maturities of other investments	570,341	323,591
Proceeds from redemptions and maturities of fixed maturity investments	240,753	421,042
Net settlements of derivative instruments	(2,510)	47,660
Net (purchases) sales of short-term investments	(510,752)	589,175
Purchase of operating affiliate	0	(546,349)
Purchases of fixed assets	(11,770)	(12,490)
Other	550	(246,590)
Net cash provided by (used for) investing activities	(312,719)	(493,189)
Financing Activities
Purchases of common shares under share repurchase program	(254,988)	(179,266)
Proceeds from common shares issued, net	(17,260)	(10,008)
Third party investment in non-redeemable noncontrolling interests	0	15,971
Dividends paid to redeemable noncontrolling interests	0	(948)
Other	48,859	(1,948)
Preferred dividends paid	(10,184)	(10,403)
Net cash provided by (used for) financing activities	(233,573)	(186,602)
Effects of exchange rate changes on foreign currency cash and restricted cash	(3,924)	(6,084)
Increase (decrease) in cash and restricted cash	1,347	76,970
Cash and restricted cash, beginning of year	1,314,771	1,290,544
Cash and restricted cash, end of period	$ 1,316,118	$ 1,367,514