Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
CASH FROM OPERATING ACTIVITIES:
Net income to common stockholders	$ 508,392	$ 394,505
Adjustments to reconcile net income to net cash from operating activities:
Net realized and unrealized gains on investments	(140,429)	(276,760)
Depreciation and amortization	76,541	78,137
Noncontrolling interests	4,402	2,560
Investment funds	(94,075)	(51,907)
Stock incentive plans	28,528	31,883
Change in:
Arbitrage trading account	(14,795)	(2,835)
Premiums and fees receivable	(107,347)	(112,420)
Reinsurance accounts	(114,298)	(42,319)
Deferred policy acquisition costs	(7,466)	4,483
Income taxes	(99,945)	(15,451)
Reserves for losses and loss expenses	230,112	422,657
Unearned premiums	176,736	121,583
Other	(103,832)	(32,258)
Net cash from operating activities	342,524	521,858
CASH USED IN INVESTING ACTIVITIES:
Proceeds from sale of fixed maturity securities	2,841,642	3,081,619
Proceeds from sale of equity securities	449,388	137,062
(Contributions to) distributions from investment funds	(3,505)	265,371
Proceeds from maturities and prepayments of fixed maturity securities	1,957,724	2,860,678
Purchase of fixed maturity securities	(5,187,501)	(6,530,466)
Purchase of equity securities	(87,059)	(17,049)
Real estate purchased	(454,410)	(159,006)
Change in loans receivable	(14,345)	32,574
Net additions to property, furniture and equipment	(35,582)	(74,268)
Change in balances due to security brokers	5,601	39,978
Cash received in connection with business disposition	8,664	0
Payment for business purchased net of cash acquired	(6,637)	(70,570)
Other	(443)	0
Net cash used in investing activities	(526,463)	(434,077)
CASH FROM (USED IN) FINANCING ACTIVITIES:
Repayment of senior notes and other debt	(23)	(1,788)
Net proceeds from issuance of debt	198,905	0
Cash dividends to common stockholders	(96,131)	(93,371)
Purchase of common treasury shares	(6,799)	(28,378)
Other, net	(4,238)	(3,835)
Net cash from (used in) financing activities	91,714	(127,372)
Net impact on cash due to change in foreign exchange rates	(38,880)	18,303
Net change in cash and cash equivalents	(131,105)	(21,288)
Cash and cash equivalents at beginning of year	950,471	795,285
Cash and cash equivalents at end of period	$ 819,366	$ 773,997