Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
CASH FROM OPERATING ACTIVITIES:
Net income to common stockholders	$ 648,884us-gaap_NetIncomeLoss	$ 499,925us-gaap_NetIncomeLoss	$ 510,592us-gaap_NetIncomeLoss
Adjustments to reconcile net income to net cash from operating activities:
Net investment gains	(254,852)us-gaap_RealizedInvestmentGainsLosses	(121,544)us-gaap_RealizedInvestmentGainsLosses	(210,465)us-gaap_RealizedInvestmentGainsLosses
Depreciation and amortization	88,836us-gaap_DepreciationAndAmortization	103,090us-gaap_DepreciationAndAmortization	103,419us-gaap_DepreciationAndAmortization
Noncontrolling interests	719	5,376	51
Investment funds	(131,649)	(67,712)	(77,015)
Stock incentive plans	28,068us-gaap_ShareBasedCompensation	23,784us-gaap_ShareBasedCompensation	26,763us-gaap_ShareBasedCompensation
Change in:
Arbitrage trading account	(50,817)	(10,324)	(1,424)
Premiums and fees receivable	(104,174)	(138,027)	(228,756)
Reinsurance accounts	(33,445)	(171,263)	(216,968)
Deferred policy acquisition costs	(42,789)	(52,124)	(38,656)
Increase (Decrease) in Income Taxes	(40,935)us-gaap_IncreaseDecreaseInIncomeTaxes	(45,613)us-gaap_IncreaseDecreaseInIncomeTaxes	5,914us-gaap_IncreaseDecreaseInIncomeTaxes
Current Income Tax Expense (Benefit)	271,306us-gaap_CurrentIncomeTaxExpenseBenefit	139,164us-gaap_CurrentIncomeTaxExpenseBenefit	179,368us-gaap_CurrentIncomeTaxExpenseBenefit
Deferred income taxes	30,812	56,281	13,240
Reserves for losses and loss expenses	376,617	372,002	406,763
Unearned premiums	277,826	323,160	279,986
Other	(58,254)	42,787	102,014
Net cash from operating activities	734,847	819,798	675,458
CASH FLOWS USED IN INVESTING ACTIVITIES:
Proceeds from sale of fixed maturity securities	633,459	1,344,707	838,576
Proceeds from sale of equity securities	113,251	267,554	409,610
Distributions from (contributions to) investment funds	69,319	(236,580)	77,930
Proceeds from maturities and prepayments of fixed maturity securities	2,605,839	2,718,156	2,291,105
Purchase of fixed maturity securities	(4,292,165)	(4,198,135)	(3,617,002)
Purchase of equity securities	(31,207)	(156,557)	(284,991)
Real estate purchased	(213,159)us-gaap_PaymentsToAcquireRealEstate	(107,352)us-gaap_PaymentsToAcquireRealEstate	(256,386)us-gaap_PaymentsToAcquireRealEstate
Proceeds from Sale of Buildings	343,723us-gaap_ProceedsFromSaleOfBuildings	0us-gaap_ProceedsFromSaleOfBuildings	0us-gaap_ProceedsFromSaleOfBuildings
Change in loans receivable	21,608	(30,974)	(124,776)
Net additions to property, furniture and equipment	(41,958)	(63,150)	(40,556)
Change in balances due from security brokers	32,617	(26,155)	(25,799)
Proceeds from Sales of Business, Affiliate and Productive Assets	15,783
Payment for business purchased, net of cash acquired	(65,421)	(56,878)	(42,779)
Net cash used in investing activities	(808,311)	(545,364)	(775,068)
CASH FLOWS FROM (USED IN) FINANCING ACTIVITIES:
Net proceeds from issuance of debt	354,012	346,822	369,291
Net proceeds from stock options exercised	0	53	7,660
Repayment of senior notes and other debt	(3,700)us-gaap_ProceedsFromRepaymentsOfDebt	(465,389)us-gaap_ProceedsFromRepaymentsOfDebt	0us-gaap_ProceedsFromRepaymentsOfDebt
Cash dividends to common stockholders	(181,489)us-gaap_PaymentsOfDividendsCommonStock	(52,717)us-gaap_PaymentsOfDividendsCommonStock	(183,947)us-gaap_PaymentsOfDividendsCommonStock
Purchase of common treasury shares	(238,933)	(166,473)	(127,663)
Other	337	7,442	31,851
Net cash from (used in) financing activities	(69,773)	(330,262)	97,192
Net impact on cash due to change in foreign exchange rates	(22,060)	(10,104)	(3,654)
Net decrease in cash and cash equivalents	(165,297)	(65,932)	(6,072)
Cash and cash equivalents at beginning of year	839,738	905,670	911,742
Cash and cash equivalents at end of year	$ 674,441	$ 839,738	$ 905,670

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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.