Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
CASH FROM OPERATING ACTIVITIES:
Net income to common stockholders	$ 466,763	$ 66,842
Adjustments to reconcile net income to net cash from operating activities:
Net investment (gains) losses	(58,903)	99,289
Depreciation and amortization	70,597	64,065
Noncontrolling interests	2,631	1,288
Investment funds	(100,246)	16,975
Stock incentive plans	23,122	25,731
Change in:
Arbitrage trading account	(139,520)	(26,158)
Premiums and fees receivable	(321,718)	(204,203)
Reinsurance accounts	(178,442)	(118,849)
Deferred policy acquisition costs	(72,125)	(31,478)
Income taxes	(71,205)	9,387
Reserves for losses and loss expenses	705,454	525,785
Unearned premiums	473,395	259,237
Other	(103,994)	(108,060)
Net cash from operating activities	695,809	579,851
CASH (USED IN) FROM INVESTING ACTIVITIES:
Proceeds from sale of fixed maturity securities	1,474,054	3,194,333
Proceeds from sale of equity securities	98,765	67,122
Distributions from investment funds	88,363	67,234
Proceeds from maturities and prepayments of fixed maturity securities	3,156,861	1,859,392
Purchase of fixed maturity securities	(6,266,934)	(4,189,664)
Purchase of equity securities	(143,836)	(35,591)
Real estate sold (purchased)	202,115	(30,178)
Change in loans receivable	(28,510)	963
Net purchases of property, furniture and equipment	(48,273)	(23,006)
Change in balances due to security brokers	65,751	(24,382)
Other	2	85
Net cash (used in) from investing activities	(1,401,642)	886,308
CASH FROM (USED IN) FINANCING ACTIVITIES:
Repayment of senior notes and other debt	(505,230)	(1,160)
Net proceeds from issuance of debt	686,893	298,447
Cash dividends to common stockholders	(21,285)	(41,420)
Purchase of common treasury shares	(29,683)	(298,902)
Other, net	(6,725)	(4,140)
Net cash from (used in) financing activities	123,970	(47,175)
Net impact on cash due to change in foreign exchange rates	(304)	(11,868)
Net change in cash and cash equivalents	(582,167)	1,407,116
Cash and cash equivalents at beginning of year	2,372,366	1,023,710
Cash and cash equivalents at end of period	$ 1,790,199	$ 2,430,826