Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
CASH FROM (USED IN) OPERATING ACTIVITIES:
Net income to common stockholders	$ 118,307us-gaap_NetIncomeLoss	$ 169,673us-gaap_NetIncomeLoss
Adjustments to reconcile net income to net cash from operating activities:
Net investment gains	(19,044)us-gaap_RealizedInvestmentGainsLosses	(52,754)us-gaap_RealizedInvestmentGainsLosses
Depreciation and amortization	19,203us-gaap_DepreciationAndAmortization	25,236us-gaap_DepreciationAndAmortization
Noncontrolling interests	137	11
Investment funds	(6,061)	(58,906)
Stock incentive plans	8,171us-gaap_ShareBasedCompensation	6,187us-gaap_ShareBasedCompensation
Change in:
Arbitrage trading account	7,692	42
Premiums and fees receivable	(71,181)	(99,306)
Reinsurance accounts	(46,260)	(49,583)
Deferred policy acquisition costs	(21,314)	(24,066)
Income taxes	44,618	70,070
Reserves for losses and loss expenses	152,925	148,204
Unearned premiums	117,403	198,933
Other	(243,584)	(190,577)
Net cash from operating activities	61,012	143,164
CASH FROM (USED IN) INVESTING ACTIVITIES:
Proceeds from sale of fixed maturity securities	466,276	328,371
Proceeds from sale of equity securities	9,785	6,457
Distributions from (contributions to) investment funds	(9,363)	158,808
Proceeds from maturities and prepayments of fixed maturity securities	655,349	546,838
Purchase of fixed maturity securities	(1,094,439)	(1,131,612)
Purchase of equity securities	(8,882)	(19,274)
Additions to real estate	(44,162)us-gaap_PaymentsToAcquireRealEstate	(35,613)us-gaap_PaymentsToAcquireRealEstate
Change in loans receivable	41,244	(29,568)
Net additions to property, furniture and equipment	(7,680)	(9,862)
Change in balances due to security brokers	(2,652)	51,557
Payment for business purchased, net of cash acquired	0	(97)
Net cash from (used in) investing activities	5,476	(133,995)
CASH USED IN FINANCING ACTIVITIES:
Repayment of senior notes and other debt	(3,240)us-gaap_RepaymentsOfLongTermDebt	(125)us-gaap_RepaymentsOfLongTermDebt
Cash dividends to common stockholders	(13,749)us-gaap_PaymentsOfDividendsCommonStock	(12,775)us-gaap_PaymentsOfDividendsCommonStock
Purchase of common treasury shares	(91,213)	(192,668)
Other, net	(1,187)	1,677
Net cash used in financing activities	(109,389)	(203,891)
Net impact on cash due to change in foreign exchange rates	(16,845)	(1,441)
Net change in cash and cash equivalents	(59,746)	(196,163)
Cash and cash equivalents at beginning of year	674,441	839,738
Cash and cash equivalents at end of period	$ 614,695	$ 643,575

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.