W. R. Berkley (WRB) 10-Q 7 Nov 16 2016 Q3 Quarterly report Financial data

Document and Entity Informatio

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2016	Nov. 02, 2016
Document and Entity Information [Abstract]
Entity Registrant Name	BERKLEY W R CORP
Entity Central Index Key	11,544
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		121,371,880

Consolidated Balance Sheet Cons

Consolidated Balance Sheet Consolidated Balance Sheet - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Assets [Abstract]
Fixed maturity securities	$ 13,616,671	$ 12,444,394
Loans receivable	158,975	150,866
Equity securities available for sale	602,965	376,697
Investment funds	1,231,700	1,170,040
Loans receivable	113,996	273,103
Real estate	1,108,482	936,367
Total investments	16,832,789	15,351,467
Cash and cash equivalents	873,064	763,631
Premiums and fees receivable	1,742,210	1,669,186
Due from reinsurers	1,692,779	1,532,829
Prepaid reinsurance premiums	429,850	394,387
Trading account receivables from brokers and clearing organizations	185,548	383,115
Deferred policy acquisition costs	564,663	513,128
Property, furniture and equipment	348,169	348,224
Federal and foreign income taxes	0	48,952
Goodwill	134,146	153,291
Accrued investment income	133,720	123,164
Other assets	408,718	442,782
Total assets	23,345,656	21,724,156
Liabilities:
Reserves for losses and loss expenses	11,097,830	10,669,150
Unearned premiums	3,408,640	3,137,133
Due to reinsurers	261,622	224,752
Trading account securities sold but not yet purchased	60,959	37,035
Deferred Tax Liabilities, Net, Current	96,885	0
Other liabilities	968,019	837,937
Subordinated debentures	727,390	340,320
Senior notes and other debt	1,762,487	1,844,621
Total liabilities	18,383,832	17,090,948
Equity:
Authorized 5,000,000 shares; issued and outstanding - none
Authorized 500,000,000 shares, issued and outstanding, net of treasury shares, 121,684,506 and 123,307,837 shares, respectively	47,024	47,024
Additional paid-in capital	1,027,465	1,005,455
Retained earnings	6,519,536	6,178,070
Accumulated other comprehensive loss	(9,808)	(66,698)
Treasury stock, at cost,113,433,412 and 111,810,081 shares, respectively	2,658,452	2,563,605
Total stockholders’ equity	4,925,765	4,600,246
Noncontrolling interests	36,059	32,962
Total equity	4,961,824	4,633,208
Total liabilities and equity	$ 23,345,656	$ 21,724,156

Consolidated Balance Sheet Con3

Consolidated Balance Sheet Consolidated Balance Sheet (Parenthetical) - $ / shares	Sep. 30, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Preferred stock, par value $.10 per share:	$ 0.1	$ 0.1
Preferred shares authorized	5,000,000	5,000,000
Preferred shares issued	0	0
Preferred shares outstanding	0	0
Common stock, par value $.20 per share:	$ 0.2	$ 0.2
Common shares authorized	500,000,000	500,000,000
Common shares issued	122,641,527	123,307,837
Common shares outstanding	122,641,527	123,307,837
Treasury stock issued at cost	112,476,391	111,810,081

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
REVENUES:
Net premiums written	$ 1,607,365	$ 1,571,037	$ 4,913,656	$ 4,690,364
Change in net unearned premiums	(21,421)	(39,479)	(240,584)	(193,752)
Net premiums earned	1,585,944	1,531,558	4,673,072	4,496,612
Net investment income	145,668	133,214	404,850	385,036
Insurance service fees	32,135	35,192	109,437	107,652
Net realized investment gains	175,738	66,419	207,508	113,020
Marketable Securities, Realized Loss, Other than Temporary Impairments, Amount	0	12,515	(18,114)	12,515
Revenues from non-insurance businesses	80,242	107,059	305,787	305,261
Other income	0	30	0	335
Total revenues	2,019,727	1,860,957	5,682,540	5,395,401
OPERATING COSTS AND EXPENSES:
Losses and loss expenses	965,856	926,355	2,852,339	2,733,298
Other operating costs and expenses	606,348	573,541	1,770,450	1,698,169
Expenses from non-insurance businesses	78,865	100,500	291,127	288,900
Interest expense	37,043	31,641	104,019	99,210
Total operating costs and expenses	1,688,112	1,632,037	5,017,935	4,819,577
Income before income taxes	331,615	228,920	664,605	575,824
Income tax expense	(110,952)	(76,184)	(214,789)	(181,595)
Net income before noncontrolling interests	220,663	152,736	449,816	394,229
Noncontrolling interests	(13)	(129)	(689)	(280)
Net income to common stockholders	$ 220,650	$ 152,607	$ 449,127	$ 393,949
NET INCOME PER SHARE:
Basic	$ 1.80	$ 1.24	$ 3.66	$ 3.17
Diluted	$ 1.72	$ 1.18	$ 3.50	$ 3.02

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income Statement - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Net income before noncontrolling interests	$ 220,663	$ 152,736	$ 449,816	$ 394,229
Other comprehensive income (loss):
Change in unrealized currency translation adjustments	(19,470)	(62,535)	(77,389)	(76,713)
Change in unrealized investment gains, net of taxes	(47,676)	4,497	134,213	(78,832)
Other comprehensive income (loss)	(67,146)	(58,038)	56,824	(155,545)
Comprehensive income	153,517	94,698	506,640	238,684
Noncontrolling interest	44	(35)	(623)	(174)
Comprehensive income to common stockholders	$ 153,561	$ 94,663	$ 506,017	$ 238,510

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity Statement - USD ($) $ in Thousands	Total	Common stocks	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]	Accumulated Translation Adjustment [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Noncontrolling Interest [Member]
Beginning and end of period at Dec. 31, 2014		$ 47,024	$ 991,512	$ 5,732,410	$ 306,199	$ (122,649)		$ (2,364,551)	$ 34,189
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock units issued including tax benefit			(25,394)
Restricted stock units expensed			23,429
Net income before noncontrolling interests	$ 394,229			393,949					280
Dividends				(43,239)
Change in unrealized investment gains, net of taxes	(78,832)				(78,773)
Unrealized gains on other-than-temporarily impaired securities					47
Change in unrealized currency translation adjustments	(76,713)					(76,713)
Stock exercised/vested								23,667
Stock repurchased								(223,652)
Contributions (distributions)									(992)
Other comprehensive income (loss)	(155,545)					(76,713)	$ (155,545)		(106)
End of period at Sep. 30, 2015			989,547	6,083,120	227,473	(199,362)	28,111	(2,564,536)	33,371
Beginning and end of period at Dec. 31, 2015	4,633,208	$ 47,024	1,005,455	6,178,070	180,695	(247,393)		(2,563,605)	32,962
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock units issued including tax benefit			(3,421)
Restricted stock units expensed			25,431
Net income before noncontrolling interests	449,816			449,127					689
Dividends				(107,661)
Change in unrealized investment gains, net of taxes	134,213				133,866
Unrealized gains on other-than-temporarily impaired securities					413
Change in unrealized currency translation adjustments	(77,389)					(77,389)
Stock exercised/vested								5,023
Stock repurchased								(99,870)
Contributions (distributions)									2,474
Other comprehensive income (loss)	56,824					(77,389)	56,824		(66)
End of period at Sep. 30, 2016	$ 4,961,824		$ 1,027,465	$ 6,519,536	$ 314,974	$ (324,782)	$ (9,808)	$ (2,658,452)	$ 36,059

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
CASH FROM (USED IN) OPERATING ACTIVITIES:
Net income to common stockholders	$ 449,127	$ 393,949
Adjustments to reconcile net income to net cash from operating activities:
Net investment gains	(189,394)	(100,505)
Depreciation and amortization	69,153	65,384
Noncontrolling interests	689	280
Investment funds	(60,387)	(50,838)
Stock incentive plans	27,033	24,052
Change in:
Arbitrage trading account	(4,777)	(4,157)
Premiums and fees receivable	(92,372)	(99,541)
Reinsurance accounts	(154,939)	(62,272)
Deferred policy acquisition costs	(51,795)	(40,216)
Income taxes	89,007	80,587
Reserves for losses and loss expenses	440,486	362,854
Unearned premiums	269,287	198,534
Other	(64,608)	(147,776)
Net cash from operating activities	726,510	620,335
CASH FROM (USED IN) INVESTING ACTIVITIES:
Proceeds from sale of fixed maturity securities	1,074,630	765,764
Proceeds from sale of equity securities	123,187	23,778
Distributions from investment funds	5,630	198,489
Proceeds from maturities and prepayments of fixed maturity securities	2,189,365	2,727,635
Purchase of fixed maturity securities	(4,280,457)	(3,387,648)
Purchase of equity securities	(127,303)	(37,754)
Real estate purchased	(207,829)	(150,940)
Change in loans receivable	159,128	35,739
Net additions to property, furniture and equipment	(37,895)	(40,262)
Change in balances due to security brokers	102,981	43,429
Proceeds from Divestiture of Businesses, Net of Cash Divested	250,216	0
Payment for business purchased net of cash aquired	(53,524)	(7,156)
Net cash from (used in) investing activities	(801,871)	171,074
CASH FROM (USED IN) FINANCING ACTIVITIES:
Repayment of senior notes and other debt	(70,567)	(279,204)
Proceeds from Issuance of Debt	386,848	1,891
Cash dividends to common stockholders	(30,654)	(43,239)
Purchase of common treasury shares	(99,870)	(223,652)
Other, net	(1,376)	(3,345)
Net cash from (used in) financing activities	184,381	(547,549)
Net impact on cash due to change in foreign exchange rates	413	(38,367)
Net change in cash and cash equivalents	109,433	205,493
Cash and cash equivalents at beginning of year	763,631	674,441
Cash and cash equivalents at end of period	$ 873,064	$ 879,934

General General

General General	9 Months Ended
	Sep. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	General The unaudited consolidated financial statements, which include the accounts of W. R. Berkley Corporation and its subsidiaries (the “Company”) have been prepared on the basis of U.S. generally accepted accounting principles (“GAAP”) for interim financial information. Accordingly, they do not include all the information and notes required by GAAP for annual financial statements. The unaudited consolidated financial statements reflect all adjustments, consisting only of normal recurring items, which are necessary to present fairly the Company’s financial position and results of operations on a basis consistent with the prior audited consolidated financial statements. Operating results for interim periods are not necessarily indicative of the results that may be expected for the year. All significant intercompany accounts and transactions have been eliminated. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the revenues and expenses reflected during the reporting period. For further information related to a description of areas of judgment and estimates and other information necessary to understand the Company’s financial position and results of operations, refer to the audited consolidated financial statements and notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015 . Reclassifications have been made in the 2015 financial statements as originally reported to conform to the presentation of the 2016 financial statements. The income tax provision has been computed based on the Company’s estimated annual effective tax rate. The effective tax rate for the quarter differs from the federal income tax rate of 35% principally because of tax-exempt investment income.

Per Share Data Per Share Data

Per Share Data Per Share Data	9 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Earnings Per Share	Per Share Data The Company presents both basic and diluted net income per share (“EPS”) amounts. Basic EPS is calculated by dividing net income by the weighted average number of common shares outstanding during the period. Diluted EPS is based upon the weighted average number of common and common equivalent shares outstanding during the period and is calculated using the treasury stock method for stock incentive plans. Common equivalent shares are excluded from the computation in periods in which they have an anti-dilutive effect. Stock options for which the exercise price exceeds the average market price over the period have an anti-dilutive effect on EPS and, accordingly, are excluded from the calculation. The weighted average number of common shares used in the computation of basic and diluted earnings per share was as follows: For the Three Months For the Nine Months Ended September 30, Ended September 30, (In thousands) 2016 2015 2016 2015 Basic 122,562 123,163 122,652 124,294 Diluted 128,556 128,947 128,501 130,563

Recent Accounting Pronouncement

Recent Accounting Pronouncements Recent Accounting Pronouncements	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements In February 2015, the Financial Accounting Standards Board ("FASB") issued ASU 2015-02, Consolidation. ASU 2015-02 makes targeted amendments to the current consolidation accounting guidance, in response to accounting complexity concerns. The guidance simplifies consolidation accounting by reducing the number of approaches to consolidation. The Company adopted this updated guidance on January 1, 2016. This adoption did not have a material effect on the Company's financial condition or results of operations, but did result in additional disclosures. In May 2015, the FASB issued ASU 2015-09, Disclosures about Short-Duration Contracts. ASU 2015-09 requires companies that issue short duration insurance contracts to disclose additional information, including: (i) incurred and paid claims development tables; (ii) frequency and severity of claims; and (iii) information about material changes in judgments made in calculating the liability for unpaid claim adjustment expenses, including reasons for the change and the effects on the financial statements. ASU 2015-09 is effective for annual periods beginning after December 15, 2015, and interim periods within annual periods beginning after December 15, 2016. The amendments in ASU 2015-09 should be applied retrospectively by providing comparative disclosures for each period presented, except for those requirements that apply only to the current period. As the requirements are disclosure only, the adoption of this guidance will not impact our financial condition or results of operations. In January 2016, the FASB issued ASU 2016-01, Financial Instruments. ASU 2016-01 which amends the accounting guidance for financial instruments to require all equity investments to be measured at fair value with changes in the fair value recognized through net income (other than those accounted for under equity method of accounting or those that result in consolidation of the investee). The updated guidance is effective for public business entities for annual reporting periods beginning after December 15, 2017 and interim periods within those years. The adoption of this guidance is not expected to have a material effect on the Company’s financial condition upon adoption, but will impact results of operations after adoption of this guidance as unrealized gains and losses on equity securities will no longer be reported in accumulated other comprehensive income (AOCI), but will instead be reported in net income. In February 2016, the FASB issued ASU 2016-02, Leases, which amends the accounting and disclosure guidance for leases. This guidance retains the two classifications of a lease, as either an operating or finance lease, both of which will require lessees to recognize a right-of-use asset and a lease liability for leases with terms of more than 12 months. The right-of-use asset and the lease liability will be determined based upon the present value of cash flows. Finance leases will reflect the financial arrangement by recognizing interest expense on the lease liability separately from the amortization expense of the right-of-use asset. Operating leases will recognize lease expense (with no separate recognition of interest expense) on a straight-line basis over the term of the lease. The accounting by lessors is not significantly changed by the updated guidance. The updated guidance is effective for reporting periods beginning after December 15, 2018, and will require that the earliest comparative period presented include the measurement and recognition of existing leases with an adjustment to equity as if the updated guidance had always been applied. The Company is currently evaluating the impact that the adoption of this guidance will have on its results of operations, financial position and liquidity. In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses, which amends the accounting guidance for credit losses on financial instruments. The updated guidance amends the current other-than-temporary impairment model for available-for-sale debt securities by requiring the recognition of impairments relating to credit losses through an allowance account and limits the amount of credit loss to the difference between a security’s amortized cost basis and its fair value. This guidance also applies a new current expected credit loss model for determining credit-related impairments for financial instruments measured at amortized cost. The updated guidance is effective for reporting periods beginning after December 15, 2019. The Company will not be able to determine the impact the adoption of this guidance will have on its results of operations, financial position or liquidity until the year the guidance becomes effective. All other recently issued but not yet effective accounting and reporting standards are either not applicable to the Company or are not expected to have a material impact on the Company.

Acquistions Acquisitions

Acquistions Acquisitions	9 Months Ended
	Sep. 30, 2016
Business Combinations [Abstract]
Business Combination Disclosure	Acquisitions/Disposition In February 2016, the Company acquired an 85% ownership interest for $42.3 million in a company engaged in the distribution of promotional merchandise. The fair value of the assets acquired and liabilities assumed have been estimated based on a preliminary valuation. The fair values of the assets and liabilities will be adjusted, as needed, following completion of the final valuation. In July 2016, the Company acquired a specialty property and casualty insurance company for $15.5 million . The following table summarizes the initial estimated fair value of net assets acquired and liabilities assumed for the business combinations completed in 2016: (In thousands) 2016 Investments $ 6,764 Cash and cash equivalents 4,266 Real estate, furniture and equipment 701 Goodwill and other intangibles assets 45,782 Premiums and service fees receivable 3,845 Other assets 5,213 Total assets acquired 66,571 Other liabilities assumed (4,931 ) Noncontrolling interest (3,850 ) Net assets acquired $ 57,790 In July 2016, the Company sold Aero Precision Industries, an aviation-related business, for $253.1 million . The business had a net carrying value of $118.2 million .

Statements of Comprehensive Inc

Statements of Comprehensive Income (Loss) Statements of Comprehensive Income (Loss) (Notes)	9 Months Ended
	Sep. 30, 2016
Equity [Abstract]
Comprehensive Income (Loss)	____ (1) Net investment (gains) losses in the consolidated statements of income. (2) Income tax expense in the consolidated statements of income.

Statements of Cash Flow Stateme

Statements of Cash Flow Statements of Cash Flow	9 Months Ended
	Sep. 30, 2016
Supplemental Cash Flow Elements [Abstract]
Cash Flow, Supplemental Disclosures	Statements of Cash Flow Interest payments were $124,791,000 and $124,632,000 and income taxes paid were $99,161,000 and $96,364,000 in the nine months ended September 30, 2016 and 2015 , respectively.

Investments In Fixed Maturity S

Investments In Fixed Maturity Securities	9 Months Ended
	Sep. 30, 2016
Debt Securities [Member]
Schedule of Marketable Securities [Line Items]
Investments In Fixed Maturity Securities	Investments in Fixed Maturity Securities At September 30, 2016 and December 31, 2015 , investments in fixed maturity securities were as follows: (In thousands) Amortized Cost Gross Unrealized Fair Value Carrying Value Gains Losses September 30, 2016 Held to maturity: State and municipal $ 71,608 $ 17,388 $ — $ 88,996 $ 71,608 Residential mortgage-backed 16,569 2,232 — 18,801 16,569 Total held to maturity 88,177 19,620 — 107,797 88,177 Available for sale: U.S. government and government agency 530,541 25,383 (931 ) 554,993 554,993 State and municipal: Special revenue 2,707,492 124,159 (1,767 ) 2,829,884 2,829,884 State general obligation 528,380 33,688 (560 ) 561,508 561,508 Pre-refunded 366,360 31,900 (9 ) 398,251 398,251 Corporate backed 374,355 15,424 (235 ) 389,544 389,544 Local general obligation 350,349 32,193 (14 ) 382,528 382,528 Total state and municipal 4,326,936 237,364 (2,585 ) 4,561,715 4,561,715 Mortgage-backed securities: Residential (1) 1,131,545 27,275 (4,859 ) 1,153,961 1,153,961 Commercial 108,928 1,032 (916 ) 109,044 109,044 Total mortgage-backed securities 1,240,473 28,307 (5,775 ) 1,263,005 1,263,005 Asset-backed 2,265,206 15,729 (12,074 ) 2,268,861 2,268,861 Corporate: Industrial 2,168,312 111,260 (3,692 ) 2,275,880 2,275,880 Financial 1,288,472 52,419 (5,384 ) 1,335,507 1,335,507 Utilities 199,941 11,593 (785 ) 210,749 210,749 Other 90,229 1,816 (13 ) 92,032 92,032 Total corporate 3,746,954 177,088 (9,874 ) 3,914,168 3,914,168 Foreign 909,765 58,477 (2,490 ) 965,752 965,752 Total available for sale 13,019,875 542,348 (33,729 ) 13,528,494 13,528,494 Total investments in fixed maturity securities $ 13,108,052 $ 561,968 $ (33,729 ) $ 13,636,291 $ 13,616,671 (In thousands) Amortized Gross Unrealized Fair Carrying Gains Losses December 31, 2015 Held to maturity: State and municipal $ 77,129 $ 16,246 $ — $ 93,375 $ 77,129 Residential mortgage-backed 19,138 2,207 — 21,345 19,138 Total held to maturity 96,267 18,453 — 114,720 96,267 Available for sale: U.S. government and government agency 645,092 27,660 (2,333 ) 670,419 670,419 State and municipal: Special revenue 2,510,816 102,909 (3,737 ) 2,609,988 2,609,988 State general obligation 583,456 28,068 (2,070 ) 609,454 609,454 Pre-refunded 439,772 32,056 (31 ) 471,797 471,797 Corporate backed 388,904 14,039 (402 ) 402,541 402,541 Local general obligation 342,158 24,270 (29 ) 366,399 366,399 Total state and municipal 4,265,106 201,342 (6,269 ) 4,460,179 4,460,179 Mortgage-backed securities: Residential (1) 1,126,382 18,935 (11,180 ) 1,134,137 1,134,137 Commercial 64,975 875 (128 ) 65,722 65,722 Total mortgage-backed securities 1,191,357 19,810 (11,308 ) 1,199,859 1,199,859 Asset-backed 1,706,694 12,892 (14,414 ) 1,705,172 1,705,172 Corporate: Industrial 1,976,393 75,168 (30,027 ) 2,021,534 2,021,534 Financial 1,153,096 31,744 (11,819 ) 1,173,021 1,173,021 Utilities 192,857 8,321 (2,527 ) 198,651 198,651 Other 81,607 245 (20 ) 81,832 81,832 Total corporate 3,403,953 115,478 (44,393 ) 3,475,038 3,475,038 Foreign 799,839 50,310 (12,689 ) 837,460 837,460 Total available for sale 12,012,041 427,492 (91,406 ) 12,348,127 12,348,127 Total investments in fixed maturity securities $ 12,108,308 $ 445,945 $ (91,406 ) $ 12,462,847 $ 12,444,394 ____________ (1) Gross unrealized losses for residential mortgage-backed securities include $857,252 and $1,269,491 as of September 30, 2016 and December 31, 2015 , respectively, related to the non-credit portion of other-than-temporary impairments (“OTTI”) recognized in accumulated other comprehensive income. The amortized cost and fair value of fixed maturity securities at September 30, 2016 , by contractual maturity, are shown below. Actual maturities may differ from contractual maturities because certain issuers may have the right to call or prepay obligations. (In thousands) Amortized Cost Fair Value Due in one year or less $ 1,032,042 $ 1,054,113 Due after one year through five years 5,068,197 5,246,081 Due after five years through ten years 3,287,833 3,500,463 Due after ten years 2,462,938 2,553,828 Mortgage-backed securities 1,257,042 1,281,806 Total $ 13,108,052 $ 13,636,291 At September 30, 2016 and 2015, there were no investments that exceeded 10% of common stockholders' equity, other than investments in United States government and government agency securities.

Investments in Equity Securitie

Investments in Equity Securities	9 Months Ended
	Sep. 30, 2016
Equity securities available for sale
Schedule of Available-for-sale Securities [Line Items]
Investments in Equity Securities	Investments in Equity Securities Available for Sale At September 30, 2016 and December 31, 2015 , investments in equity securities were as follows: (In thousands) Cost Gross Unrealized Fair Value Carrying Value Gains Losses September 30, 2016 Common stocks $ 37,897 $ 215 $ (2,441 ) $ 35,671 $ 35,671 Preferred stocks 125,759 6,573 (9,028 ) 123,304 123,304 Total $ 163,656 $ 6,788 $ (11,469 ) $ 158,975 $ 158,975 December 31, 2015 Common stocks $ 56,462 $ — $ (19,189 ) $ 37,273 $ 37,273 Preferred stocks 108,730 8,216 (3,353 ) 113,593 113,593 Total $ 165,192 $ 8,216 $ (22,542 ) $ 150,866 $ 150,866

Arbitrage Trading Account Arbit

Arbitrage Trading Account Arbitrage Trading Account (Notes)	9 Months Ended
	Sep. 30, 2016
Schedule of Investments [Abstract]
Arbitrage Trading Account and Arbitrage Funds [Text Block]	Arbitrage Trading Account At September 30, 2016 and December 31, 2015 , the fair and carrying values of the arbitrage trading account were $603 million and $377 million , respectively. The primary focus of the trading account is merger arbitrage. Merger arbitrage is the business of investing in the securities of publicly held companies which are the targets in announced tender offers and mergers. Arbitrage investing differs from other types of investing in its focus on transactions and events believed likely to bring about a change in value over a relatively short time period (usually four months or less). The Company uses put options, call options and swap contracts in order to mitigate the impact of potential changes in market conditions on the merger arbitrage trading account. These options and contracts are reported at fair value. As of September 30, 2016 , the fair value of long option contracts outstanding was $1.2 million (notional amount of $53.9 million ) and the fair value of short option contracts outstanding was $0.7 million (notional amount of $103.6 million ). Other than with respect to the use of these trading account securities, the Company does not make use of derivatives.

Net Investment Income Net Inves

Net Investment Income Net Investment Income	9 Months Ended
	Sep. 30, 2016
Income Statement [Abstract]
Net Investment Income	Net Investment Income Net investment income consists of the following: For the Three Months For the Nine Months Ended September 30, Ended September 30, (In thousands) 2016 2015 2016 2015 Investment income earned on: Fixed maturity securities, including cash and cash equivalents and loans receivable $ 114,271 $ 104,936 $ 331,448 $ 318,095 Investment funds 25,293 22,926 60,385 50,838 Arbitrage trading account 6,441 2,608 12,883 11,470 Equity securities available for sale 1,069 1,109 3,217 3,513 Real estate 585 4,389 4,552 9,270 Gross investment income 147,659 135,968 412,485 393,186 Investment expense (1,991 ) (2,754 ) (7,635 ) (8,150 ) Net investment income $ 145,668 $ 133,214 $ 404,850 $ 385,036

Investment Funds Investment Fun

Investment Funds Investment Funds	9 Months Ended
	Sep. 30, 2016
Equity Method Investments and Joint Ventures [Abstract]
Net Investment Income	Investment Funds The Company evaluates whether it is an investor in a variable interest entity (VIE). Such entities do not have sufficient equity at risk to finance their activities without additional subordinated financial support, or the equity investors, as a group, do not have the characteristics of a controlling financial interest (primary beneficiary). The Company determines whether it is the primary beneficiary of an entity subject to consolidation based on a qualitative assessment of the VIE's capital structure, contractual terms, nature of the VIE's operations and purpose, and the Company's relative exposure to the related risks of the VIE on the date it becomes initially involved in the VIE and on an ongoing basis. The Company is not the primary beneficiary in any of its investment funds, and accordingly, carries its interests in investments funds under the equity method of accounting. The Company’s maximum exposure to loss with respect to these investments is limited to the carrying amount reported on the Company’s consolidated balance sheet and any unfunded commitment. Investment funds consist of the following: Carrying Value as of Income (Loss) from Investment Funds September 30, December 31, For the Nine Months Ended September 30, (In thousands) 2016 2015 2016 2015 Real estate $ 646,102 $ 580,830 $ 33,028 $ 51,467 Energy 80,900 93,719 7,174 (25,124 ) Hedge equity 71,371 70,580 791 (3,925 ) Other funds 433,327 424,911 19,392 28,420 Total $ 1,231,700 $ 1,170,040 $ 60,385 $ 50,838 The Company's share of the earnings or losses of investment funds is generally reported on a one-quarter lag in order to facilitate the timely completion of the Company's consolidated financial statements. Other funds include private equity investments carried on the equity method of accounting, which includes a publicly traded common stock investment in HealthEquity, Inc. (HQY). Our ownership interest in HQY as of September 30, 2016 is approximately 21% with a fair value of $453 million and a carrying value of $53.1 million . In October 2016, the Company sold approximately 2.2 million shares in HQY and recognized a realized investment gain of approximately $65 million. Following the completion of the sale, the Company will report its investment in HQY at fair value.

Real Estate Real Estate

Real Estate Real Estate	9 Months Ended
	Sep. 30, 2016
Real Estate [Abstract]
Real Estate	Real Estate Investment in real estate represents directly owned property held for investment, as follows: Carrying Value September 30, December 31, (In thousands) 2016 2015 Properties in operation $ 441,795 $ 226,055 Properties under development 666,687 710,312 Total $ 1,108,482 $ 936,367 In 2016, properties in operation included a long-term ground lease in Washington, D.C., a hotel in Memphis, Tennessee, an office complex in New York City and office buildings in West Palm Beach and Palm Beach, Florida. Properties in operation are net of accumulated depreciation and amortization of $13,345,000 and $9,073,000 as of September 30, 2016 and December 31, 2015, respectively. Related depreciation expense was $4,117,000 and $5,991,000 for the nine months ended September 30, 2016 and 2015, respectively. Future minimum rental income expected on operating leases relating to properties in operation is $2,982,866 in 2016, $16,900,586 in 2017, $22,572,465 in 2018, $20,707,015 in 2019, $19,471,136 in 2020, $19,649,571 in 2021 and $411,667,096 thereafter. Properties under development include an office building in London and a mixed-use project in Washington, D.C.

Loans Receivable Loans Receivab

Loans Receivable Loans Receivable	9 Months Ended
	Sep. 30, 2016
Receivables [Abstract]
Loans Receivable	Loans Receivable Loans receivable are as follows: (In thousands) September 30, 2016 December 31, 2015 Amortized cost (net of valuation allowance): Real estate loans $ 96,312 $ 200,499 Commercial loans 17,684 72,604 Total $ 113,996 $ 273,103 Fair value: Real estate loans $ 97,296 $ 201,641 Commercial loans 19,187 74,106 Total $ 116,483 $ 275,747 Valuation allowance: Specific $ 1,025 $ — General 2,197 2,094 Total $ 3,222 $ 2,094 For the Three Months Ended September 30, 2016 2015 Increase in valuation allowance $ 467 $ 19 For the Nine Months Ended September 30, 2016 2015 Increase (decrease) in valuation allowance $ 1,128 $ (81 ) Loans receivable in non-accrual status were $9.1 million and $3.1 million as of September 30, 2016 and December 31, 2015, respectively. The Company monitors the performance of its loans receivable and assesses the ability of the borrower to pay principal and interest based upon loan structure, underlying property values, cash flow and related financial and operating performance of the property and market conditions. Loans receivable with a potential for default are further assessed using discounted cash flow analysis and comparable cost and sales methodologies, if appropriate. The real estate loans are secured by commercial real estate primarily located in North Carolina, Ohio and New York. These loans generally earn interest at floating LIBOR-based interest rates and have maturities (inclusive of extension options) through August 2025. The commercial loans are with small business owners who have secured the related financing with the assets of the business. Commercial loans generally earn interest on a fixed basis and have varying maturities not exceeding 10 years. In evaluating the real estate loans, the Company considers their credit quality indicators, including loan to value ratios, which compare the outstanding loan amount to the estimated value of the property, the borrower’s financial condition and performance with respect to loan terms, the position in the capital structure, the overall leverage in the capital structure and other market conditions. Based on these considerations, none of the real estate loans were considered to be impaired at September 30, 2016, and accordingly, the Company determined that a specific valuation allowance was not required.

Realized And Unrealized Investm

Realized And Unrealized Investment Gains (Losses)	9 Months Ended
	Sep. 30, 2016
Realized and Unrealized Investment Gains (Losses) [Abstract]
Realized and Unrealized Investment Gains (Losses)	Realized and Unrealized Investment Gains (Losses) Realized and unrealized investment gains (losses) are as follows: For the Three Months Ended September 30, For the Nine Months Ended September 30, (In thousands) 2016 2015 2016 2015 Realized investment gains (losses): Fixed maturity securities: Gains $ 33,798 $ 1,341 $ 66,972 $ 8,178 Losses (1,150 ) (2,171 ) (5,570 ) (2,810 ) Equity securities available for sale 8,441 (21 ) 13,037 9,639 Investment funds (3,788 ) 70,648 (9,041 ) 92,821 Real estate 687 — 5,247 — Other (1) 137,750 (3,378 ) 136,863 5,192 Net realized gains on investments sales 175,738 66,419 207,508 113,020 Other-than-temporary impairments (2) — (12,515 ) (18,114 ) (12,515 ) Net investment gains 175,738 53,904 189,394 100,505 Income tax expense (61,508 ) (18,866 ) (66,288 ) (35,177 ) After-tax net realized investment gains $ 114,230 $ 35,038 $ 123,106 $ 65,328 Change in unrealized investment gains (losses) of available for sale securities: Fixed maturity securities $ (45,388 ) $ 2,449 $ 169,933 $ (102,863 ) Previously impaired fixed maturity securities (1,406 ) 50 413 73 Equity securities available for sale (28,517 ) (2,353 ) 12,433 (15,977 ) Investment funds 3,143 (7,876 ) 16,028 (16,417 ) Total change in unrealized investment gains (losses) (72,168 ) (7,730 ) 198,807 (135,184 ) Income tax benefit (expense) 24,493 12,229 (64,594 ) 56,354 Noncontrolling interests 57 94 66 106 After-tax change in unrealized investment gains (losses) of available for sale securities $ (47,618 ) $ 4,593 $ 134,279 $ (78,724 ) ______________________ (1) Other includes a gain of $ 134.9 million from the sale of Aero Precision Industries, and certain related aviation services business, for the three and nine months ended September 30, 2016. (2) Other than temporary impairments (OTTI) for the nine months ended September 30, 2016 of $18.1 million were related to equity securities available for sale. OTTI for the three and nine months ended September 30, 2015 of $12.5 million were related to equity securities available for sale and fixed maturity securities of $3.5 million and $9.0 million, respectively.

Securities In An Unrealized Los

Securities In An Unrealized Loss Position	9 Months Ended
	Sep. 30, 2016
Investments [Abstract]
Securities in Unrealized Loss Position	Securities in an Unrealized Loss Position The following tables summarize all securities in an unrealized loss position at September 30, 2016 and December 31, 2015 by the length of time those securities have been continuously in an unrealized loss position: Less Than 12 Months 12 Months or Greater Total (In thousands) Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses September 30, 2016 U.S. government and government agency $ 54,550 $ 279 $ 39,092 $ 652 $ 93,642 $ 931 State and municipal 217,215 1,095 138,082 1,490 355,297 2,585 Mortgage-backed securities 251,969 1,851 105,927 3,924 357,896 5,775 Asset-backed securities 918,983 5,718 214,436 6,356 1,133,419 12,074 Corporate 337,940 2,152 98,162 7,722 436,102 9,874 Foreign 52,233 640 30,842 1,850 83,075 2,490 Fixed maturity securities 1,832,890 11,735 626,541 21,994 2,459,431 33,729 Common stocks 18,112 779 8,116 1,662 26,228 2,441 Preferred stocks 46,135 8,199 24,845 829 70,980 9,028 Equity securities available for sale 64,247 8,978 32,961 2,491 97,208 11,469 Total $ 1,897,137 $ 20,713 $ 659,502 $ 24,485 $ 2,556,639 $ 45,198 December 31, 2015 U.S. government and government agency $ 101,660 $ 487 $ 64,500 $ 1,846 $ 166,160 $ 2,333 State and municipal 501,952 4,404 106,681 1,865 608,633 6,269 Mortgage-backed securities 381,986 3,639 184,807 7,669 566,793 11,308 Asset-backed securities 1,091,078 7,703 190,467 6,711 1,281,545 14,414 Corporate 1,232,940 35,406 76,797 8,987 1,309,737 44,393 Foreign 169,190 8,822 19,528 3,867 188,718 12,689 Fixed maturity securities 3,478,806 60,461 642,780 30,945 4,121,586 91,406 Common stocks 18,641 18,005 7,829 1,184 26,470 19,189 Preferred stocks — — 22,320 3,353 22,320 3,353 Equity securities available for sale 18,641 18,005 30,149 4,537 48,790 22,542 Total $ 3,497,447 $ 78,466 $ 672,929 $ 35,482 $ 4,170,376 $ 113,948 Fixed Maturity Securities – A summary of the Company’s non-investment grade fixed maturity securities that were in an unrealized loss position at September 30, 2016 is presented in the table below: ($ in thousands) Number of Securities Aggregate Fair Value Gross Unrealized Loss Corporate 10 $ 27,531 $ 3,045 Mortgage-backed securities 11 23,921 1,229 Foreign government 4 23,001 1,101 Asset-backed securities 5 8,418 405 State and municipal 1 7,007 25 Total 31 $ 89,878 $ 5,805 For OTTI of fixed maturity securities that management does not intend to sell or, to be required to sell, the portion of the decline in value that is considered to be due to credit factors is recognized in earnings, and the portion of the decline in value that is considered to be due to non-credit factors is recognized in other comprehensive income. The Company has evaluated its fixed maturity securities in an unrealized loss position and believes the unrealized losses are due primarily to temporary market and sector-related factors rather than to issuer-specific factors. None of these securities are delinquent or in default under financial covenants. Based on its assessment of these issuers, the Company expects them to continue to meet their contractual payment obligations as they become due and does not consider any of these securities to be OTTI. Preferred Stocks – At September 30, 2016 , there were three preferred stocks in an unrealized loss position, with an aggregate fair value of $71 million and a gross unrealized loss of $9 million . Based upon management’s view of the underlying value of these securities, the Company does not consider these equity securities to be OTTI. Common Stocks – At September 30, 2016 , there were three common stocks in an unrealized loss position, with an aggregate fair value of $26 million and a gross unrealized loss of $2 million . Based on management's view of the underlying securities, the Company does not consider these equity securities to be OTTI. Loans Receivable – The Company monitors the performance of its loans receivable, including current market conditions for each loan and the ability to collect principal and interest. For loans where the Company determines it is probable that the contractual terms will not be met, an analysis is performed and a valuation reserve is established, if necessary, with a charge to earnings. Loans receivable are reported net of a valuation reserve of $3 million and $2 million at September 30, 2016 and December 31, 2015, respectively.

Fair Value Measurements Fair Va

Fair Value Measurements Fair Value Measurements	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Fair Value Disclosures	Fair Value Measurements The Company’s fixed maturity and equity securities classified as available for sale and its trading account securities are carried at fair value. Fair value is defined as “the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date.” The Company utilizes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three broad levels, as follows: Level 1 - Quoted prices (unadjusted) in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. Level 2 - Quoted prices for similar assets or valuations based on inputs that are observable. Level 3 - Estimates of fair value based on internal pricing methodologies using unobservable inputs. Unobservable inputs are only used to measure fair value to the extent that observable inputs are not available. Substantially, all of the Company’s fixed maturity securities were priced by independent pricing services. The prices provided by the independent pricing services are estimated based on observable market data in active markets utilizing pricing models and processes, which may include benchmark yields, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers, sector groupings, matrix pricing and reference data. The pricing services may prioritize inputs differently on any given day for any security based on market conditions, and not all inputs are available for each security evaluation on any given day. The pricing services used by the Company have indicated that they will only produce an estimate of fair value if objectively verifiable information is available. The determination of whether markets are active or inactive is based upon the volume and level of activity for a particular asset class. The Company reviews the prices provided by pricing services for reasonableness and periodically performs independent price tests of a sample of securities to ensure proper valuation. If prices from independent pricing services are not available for fixed maturity securities, the Company estimates the fair value. For Level 2 securities, the Company utilizes pricing models and processes which may include benchmark yields, sector groupings, matrix pricing, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, bids, offers and reference data. Where broker quotes are used, the Company generally requests two or more quotes and sets a price within the range of quotes received based on its assessment of the credibility of the quote and its own evaluation of the security. The Company generally does not adjust quotes received from brokers. For securities traded only in private negotiations, the Company determines fair value based primarily on the cost of such securities, which is adjusted to reflect prices of recent placements of securities of the same issuer, financial projections, credit quality and business developments of the issuer and other relevant information. For Level 3 securities, the Company generally uses a discounted cash flow model to estimate the fair value of fixed maturity securities. The cash flow models are based upon assumptions as to prevailing credit spreads, interest rate and interest rate volatility, time to maturity and subordination levels. Projected cash flows are discounted at rates that are adjusted to reflect illiquidity, where appropriate. The following tables present the assets and liabilities measured at fair value on a recurring basis as of September 30, 2016 and December 31, 2015 by level: (In thousands) Total Level 1 Level 2 Level 3 September 30, 2016 Assets: Fixed maturity securities available for sale: U.S. government and government agency $ 554,993 $ — $ 554,993 $ — State and municipal 4,561,715 — 4,561,715 — Mortgage-backed securities 1,263,005 — 1,263,005 — Asset-backed securities 2,268,861 — 2,268,676 185 Corporate 3,914,168 — 3,914,168 — Foreign government 965,752 — 965,752 — Total fixed maturity securities available for sale 13,528,494 — 13,528,309 185 Equity securities available for sale: Common stocks 35,671 27,555 — 8,116 Preferred stocks 123,304 — 119,630 3,674 Total equity securities available for sale 158,975 27,555 119,630 11,790 Arbitrage trading account 602,965 320,280 282,685 — Total $ 14,290,434 $ 347,835 $ 13,930,624 $ 11,975 Liabilities: Trading account securities sold but not yet purchased $ 60,959 $ 60,947 $ 12 $ — December 31, 2015 Assets: Fixed maturity securities available for sale: U.S. government and government agency $ 670,419 $ — $ 670,419 $ — State and municipal 4,460,179 — 4,460,179 — Mortgage-backed securities 1,199,859 — 1,199,859 — Asset-backed securities 1,705,172 — 1,704,973 199 Corporate 3,475,038 — 3,474,884 154 Foreign government 837,460 — 837,460 — Total fixed maturity securities available for sale 12,348,127 — 12,347,774 353 Equity securities available for sale: Common stocks 37,273 29,444 — 7,829 Preferred stocks 113,593 — 109,969 3,624 Total equity securities available for sale 150,866 29,444 109,969 11,453 Arbitrage trading account 376,697 256,914 119,607 176 Total $ 12,875,690 $ 286,358 $ 12,577,350 $ 11,982 Liabilities: Trading account securities sold but not yet purchased $ 37,035 $ 35,559 $ 1,476 $ — There were no significant transfers between Levels 1 and 2 during the nine months ended September 30, 2016 or during the year ended December 31, 2015 . The following tables summarize changes in Level 3 assets and liabilities for the nine months ended September 30, 2016 and for the year ended December 31, 2015 : Gains (Losses) Included in: (In thousands) Beginning Balance Earnings (Losses) Other Comprehensive Income (Loss) Impairments Purchases (Sales) Paydowns / Maturities Transfers Ending Balance In / (Out) Nine months ended September 30, 2016: Assets: Fixed maturities securities available for sale: Asset-backed securities $ 199 $ 3 $ 13 $ — $ — $ — $ (30 ) $ — $ 185 Corporate 154 177 — — — (331 ) — — — Total 353 180 13 — — (331 ) (30 ) — 185 Equity securities available for sale: Common stocks 7,829 — (478 ) — 765 — — — 8,116 Preferred stocks 3,624 50 — — — — — — 3,674 Total 11,453 50 (478 ) — 765 — — — 11,790 Arbitrage trading account 176 (176 ) — — — — — — — Total $ 11,982 $ 54 $ (465 ) $ — $ 765 $ (331 ) $ (30 ) $ — $ 11,975 Year ended December 31, 2015: Assets: Fixed maturities securities available for sale: Asset-backed securities $ 20,611 $ 19 $ 191 $ — $ — $ — $ (1,820 ) $ (18,802 ) $ 199 Corporate 154 — — — — — — — 154 Total 20,765 19 191 — — — (1,820 ) (18,802 ) 353 Equity securities available for sale: Common stocks 10,741 — (273 ) (2,331 ) — (308 ) — — 7,829 Preferred stocks 3,713 (89 ) — — — — — — 3,624 Total 14,454 (89 ) (273 ) (2,331 ) — (308 ) — — 11,453 Arbitrage trading account 720 (799 ) — — 72,640 (71,921 ) — (464 ) 176 Total $ 35,939 $ (869 ) $ (82 ) $ (2,331 ) $ 72,640 $ (72,229 ) $ (1,820 ) $ (19,266 ) $ 11,982 During the nine months ended September 30, 2016, there were no t ransfers out of Level 3. During the year ended December 31, 2015, five securities were transferred out of Level 3 as an observable price became available. Fair Value of Financial Instruments The following table presents the carrying amounts and estimated fair values of the Company’s financial instruments: September 30, 2016 December 31, 2015 (In thousands) Carrying Value Fair Value Carrying Value Fair Value Assets: Fixed maturity securities $ 13,616,671 $ 13,636,291 $ 12,444,394 $ 12,462,847 Equity securities available for sale 158,975 158,975 150,866 150,866 Arbitrage trading account 602,965 602,965 376,697 376,697 Loans receivable 113,996 116,483 273,103 275,747 Cash and cash equivalents 873,064 873,064 763,631 763,631 Trading account receivables from brokers and clearing organizations 185,548 185,548 383,115 383,115 Due from broker — — 1,713 1,713 Liabilities: Due to broker 101,405 101,405 — — Trading account securities sold but not yet purchased 60,959 60,959 37,035 37,035 Subordinated debentures 727,390 779,056 340,320 355,880 Senior notes and other debt 1,762,487 1,997,430 1,844,621 2,029,572 The estimated fair values of the Company’s fixed maturity securities, equity securities available for sale and arbitrage trading account securities are based on various valuation techniques that rely on fair value measurements as described in Note 16 above. The fair value of loans receivable are estimated by using current institutional purchaser yield requirements for loans with similar credit characteristics, which is considered a Level 2 input. The fair value of the senior notes and other debt and the subordinated debentures is based on spreads for similar securities, which is considered a Level 2 input.

Reinsurance Reinsurance

Reinsurance Reinsurance	9 Months Ended
	Sep. 30, 2016
Insurance [Abstract]
Reinsurance [Text Block]	Reinsurance The following is a summary of reinsurance financial information: For the Three Months For the Nine Months Ended September 30, Ended September 30, (In thousands) 2016 2015 2016 2015 Written premiums: Direct $ 1,643,870 $ 1,601,344 $ 5,061,646 $ 4,852,584 Assumed 224,979 221,237 702,265 633,200 Ceded (261,484 ) (251,544 ) (850,255 ) (795,420 ) Total net premiums written $ 1,607,365 $ 1,571,037 $ 4,913,656 $ 4,690,364 Earned premiums: Direct $ 1,647,033 $ 1,575,624 $ 4,824,768 $ 4,646,343 Assumed 216,758 217,668 635,443 632,362 Ceded (277,847 ) (261,734 ) (787,139 ) (782,093 ) Total net premiums earned $ 1,585,944 $ 1,531,558 $ 4,673,072 $ 4,496,612 Ceded losses and loss expenses incurred $ 213,065 $ 123,765 $ 507,258 $ 374,084 Ceded commissions earned $ 47,315 $ 45,946 $ 143,809 $ 129,766 The Company reinsures a portion of its insurance exposures in order to reduce its net liability on individual risks and catastrophe losses. The Company also cedes premiums to state assigned risk plans and captive insurance companies. Estimated amounts due from reinsurers are reported net of reserves for uncollectible reinsurance of $1 million as of September 30, 2016 and December 31, 2015 .

Fair Value Of Financial Instrum

Fair Value Of Financial Instruments Fair Value of Financial Instruments (Notes)	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Fair Value Disclosures	Fair Value Measurements The Company’s fixed maturity and equity securities classified as available for sale and its trading account securities are carried at fair value. Fair value is defined as “the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date.” The Company utilizes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three broad levels, as follows: Level 1 - Quoted prices (unadjusted) in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. Level 2 - Quoted prices for similar assets or valuations based on inputs that are observable. Level 3 - Estimates of fair value based on internal pricing methodologies using unobservable inputs. Unobservable inputs are only used to measure fair value to the extent that observable inputs are not available. Substantially, all of the Company’s fixed maturity securities were priced by independent pricing services. The prices provided by the independent pricing services are estimated based on observable market data in active markets utilizing pricing models and processes, which may include benchmark yields, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers, sector groupings, matrix pricing and reference data. The pricing services may prioritize inputs differently on any given day for any security based on market conditions, and not all inputs are available for each security evaluation on any given day. The pricing services used by the Company have indicated that they will only produce an estimate of fair value if objectively verifiable information is available. The determination of whether markets are active or inactive is based upon the volume and level of activity for a particular asset class. The Company reviews the prices provided by pricing services for reasonableness and periodically performs independent price tests of a sample of securities to ensure proper valuation. If prices from independent pricing services are not available for fixed maturity securities, the Company estimates the fair value. For Level 2 securities, the Company utilizes pricing models and processes which may include benchmark yields, sector groupings, matrix pricing, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, bids, offers and reference data. Where broker quotes are used, the Company generally requests two or more quotes and sets a price within the range of quotes received based on its assessment of the credibility of the quote and its own evaluation of the security. The Company generally does not adjust quotes received from brokers. For securities traded only in private negotiations, the Company determines fair value based primarily on the cost of such securities, which is adjusted to reflect prices of recent placements of securities of the same issuer, financial projections, credit quality and business developments of the issuer and other relevant information. For Level 3 securities, the Company generally uses a discounted cash flow model to estimate the fair value of fixed maturity securities. The cash flow models are based upon assumptions as to prevailing credit spreads, interest rate and interest rate volatility, time to maturity and subordination levels. Projected cash flows are discounted at rates that are adjusted to reflect illiquidity, where appropriate. The following tables present the assets and liabilities measured at fair value on a recurring basis as of September 30, 2016 and December 31, 2015 by level: (In thousands) Total Level 1 Level 2 Level 3 September 30, 2016 Assets: Fixed maturity securities available for sale: U.S. government and government agency $ 554,993 $ — $ 554,993 $ — State and municipal 4,561,715 — 4,561,715 — Mortgage-backed securities 1,263,005 — 1,263,005 — Asset-backed securities 2,268,861 — 2,268,676 185 Corporate 3,914,168 — 3,914,168 — Foreign government 965,752 — 965,752 — Total fixed maturity securities available for sale 13,528,494 — 13,528,309 185 Equity securities available for sale: Common stocks 35,671 27,555 — 8,116 Preferred stocks 123,304 — 119,630 3,674 Total equity securities available for sale 158,975 27,555 119,630 11,790 Arbitrage trading account 602,965 320,280 282,685 — Total $ 14,290,434 $ 347,835 $ 13,930,624 $ 11,975 Liabilities: Trading account securities sold but not yet purchased $ 60,959 $ 60,947 $ 12 $ — December 31, 2015 Assets: Fixed maturity securities available for sale: U.S. government and government agency $ 670,419 $ — $ 670,419 $ — State and municipal 4,460,179 — 4,460,179 — Mortgage-backed securities 1,199,859 — 1,199,859 — Asset-backed securities 1,705,172 — 1,704,973 199 Corporate 3,475,038 — 3,474,884 154 Foreign government 837,460 — 837,460 — Total fixed maturity securities available for sale 12,348,127 — 12,347,774 353 Equity securities available for sale: Common stocks 37,273 29,444 — 7,829 Preferred stocks 113,593 — 109,969 3,624 Total equity securities available for sale 150,866 29,444 109,969 11,453 Arbitrage trading account 376,697 256,914 119,607 176 Total $ 12,875,690 $ 286,358 $ 12,577,350 $ 11,982 Liabilities: Trading account securities sold but not yet purchased $ 37,035 $ 35,559 $ 1,476 $ — There were no significant transfers between Levels 1 and 2 during the nine months ended September 30, 2016 or during the year ended December 31, 2015 . The following tables summarize changes in Level 3 assets and liabilities for the nine months ended September 30, 2016 and for the year ended December 31, 2015 : Gains (Losses) Included in: (In thousands) Beginning Balance Earnings (Losses) Other Comprehensive Income (Loss) Impairments Purchases (Sales) Paydowns / Maturities Transfers Ending Balance In / (Out) Nine months ended September 30, 2016: Assets: Fixed maturities securities available for sale: Asset-backed securities $ 199 $ 3 $ 13 $ — $ — $ — $ (30 ) $ — $ 185 Corporate 154 177 — — — (331 ) — — — Total 353 180 13 — — (331 ) (30 ) — 185 Equity securities available for sale: Common stocks 7,829 — (478 ) — 765 — — — 8,116 Preferred stocks 3,624 50 — — — — — — 3,674 Total 11,453 50 (478 ) — 765 — — — 11,790 Arbitrage trading account 176 (176 ) — — — — — — — Total $ 11,982 $ 54 $ (465 ) $ — $ 765 $ (331 ) $ (30 ) $ — $ 11,975 Year ended December 31, 2015: Assets: Fixed maturities securities available for sale: Asset-backed securities $ 20,611 $ 19 $ 191 $ — $ — $ — $ (1,820 ) $ (18,802 ) $ 199 Corporate 154 — — — — — — — 154 Total 20,765 19 191 — — — (1,820 ) (18,802 ) 353 Equity securities available for sale: Common stocks 10,741 — (273 ) (2,331 ) — (308 ) — — 7,829 Preferred stocks 3,713 (89 ) — — — — — — 3,624 Total 14,454 (89 ) (273 ) (2,331 ) — (308 ) — — 11,453 Arbitrage trading account 720 (799 ) — — 72,640 (71,921 ) — (464 ) 176 Total $ 35,939 $ (869 ) $ (82 ) $ (2,331 ) $ 72,640 $ (72,229 ) $ (1,820 ) $ (19,266 ) $ 11,982 During the nine months ended September 30, 2016, there were no t ransfers out of Level 3. During the year ended December 31, 2015, five securities were transferred out of Level 3 as an observable price became available. Fair Value of Financial Instruments The following table presents the carrying amounts and estimated fair values of the Company’s financial instruments: September 30, 2016 December 31, 2015 (In thousands) Carrying Value Fair Value Carrying Value Fair Value Assets: Fixed maturity securities $ 13,616,671 $ 13,636,291 $ 12,444,394 $ 12,462,847 Equity securities available for sale 158,975 158,975 150,866 150,866 Arbitrage trading account 602,965 602,965 376,697 376,697 Loans receivable 113,996 116,483 273,103 275,747 Cash and cash equivalents 873,064 873,064 763,631 763,631 Trading account receivables from brokers and clearing organizations 185,548 185,548 383,115 383,115 Due from broker — — 1,713 1,713 Liabilities: Due to broker 101,405 101,405 — — Trading account securities sold but not yet purchased 60,959 60,959 37,035 37,035 Subordinated debentures 727,390 779,056 340,320 355,880 Senior notes and other debt 1,762,487 1,997,430 1,844,621 2,029,572 The estimated fair values of the Company’s fixed maturity securities, equity securities available for sale and arbitrage trading account securities are based on various valuation techniques that rely on fair value measurements as described in Note 16 above. The fair value of loans receivable are estimated by using current institutional purchaser yield requirements for loans with similar credit characteristics, which is considered a Level 2 input. The fair value of the senior notes and other debt and the subordinated debentures is based on spreads for similar securities, which is considered a Level 2 input.

Restricted Stock Units Restrict

Restricted Stock Units Restricted Stock Units (Notes)	9 Months Ended
	Sep. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Restricted Stock Units	Restricted Stock Units Pursuant to its stock incentive plan, the Company may issue restricted stock units (RSUs) to employees of the Company and its subsidiaries. The RSUs generally vest three to five years from the award date and are subject to other vesting and forfeiture provisions contained in the award agreement. RSUs are expensed pro-ratably over the vesting period. RSU expenses were $25 million and $23 million for the nine months ended September 30, 2016 and 2015 , respectively. A summary of RSUs issued in the nine months ended September 30, 2016 and 2015 follows: ($ in thousands) Units Fair Value Nine months ended September 30, 2016 990,487 $ 57,959 2015 971,457 $ 54,439

Litigation and Contingent Liabi

Litigation and Contingent Liabilities Litigation and Contingent Liabilities	9 Months Ended
	Sep. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies Disclosure [Text Block]	Litigation and Contingent Liabilities In the ordinary course of business, the Company is subject to disputes, litigation and arbitration arising from its insurance and reinsurance businesses. These matters are generally related to insurance and reinsurance claims and are considered in the establishment of loss and loss expense reserves. In addition, the Company may also become involved in legal actions which seek extra-contractual damages, punitive damages or penalties, including claims alleging bad faith in handling of insurance claims. The Company expects its ultimate liability with respect to such matters will not be material to its financial condition. However, adverse outcomes on such matters are possible, from time to time, and could be material to the Company’s results of operations in any particular financial reporting period.

Industry Segments

Industry Segments	9 Months Ended
	Sep. 30, 2016
Segment Reporting [Abstract]
Industry Segments	The Company’s reportable segments include the following two business segments: • Insurance - primarily commercial insurance business, including excess and surplus lines and admitted lines in the United States, United Kingdom, Continental Europe, South America, Canada, Scandinavia, Asia and Australia; and • Reinsurance - reinsurance business on a facultative and treaty basis, primarily in the United States, United Kingdom, Continental Europe, Australia, the Asia-Pacific Region, and South Africa. Commencing with the first quarter of 2016, the Company changed the aggregation of its business segments. Insurance-Domestic operating units and Insurance-International operating units, previously reported separately, have been aggregated into the Insurance segment. The segment disclosures for prior periods have been revised to be consistent with the new reportable business segment presentation. The accounting policies of the segments are the same as those described in the summary of significant accounting policies. Income tax expense and benefits are calculated based upon the Company's overall effective tax rate. Summary financial information about the Company's reporting segments is presented in the following tables. Income (loss) before income taxes by segment includes allocated investment income. Identifiable assets by segment are those assets used in or allocated to the operation of each segment. Revenues (In thousands) Earned Premiums Investment Income Other Total Pre-Tax Income (Loss) Net Income (Loss) to Common Stockholders Three months ended September 30, 2016 Insurance $ 1,431,664 $ 117,388 $ 22,819 $ 1,571,871 $ 215,649 $ 144,310 Reinsurance 154,280 21,478 — 175,758 22,171 15,167 Corporate, other and eliminations (1) — 6,802 89,560 96,362 (81,941 ) (53,055 ) Net investment gains — — 175,736 175,736 175,736 114,228 Total $ 1,585,944 $ 145,668 $ 288,115 $ 2,019,727 $ 331,615 $ 220,650 Three months ended September 30, 2015 Insurance $ 1,379,501 $ 106,989 $ 23,021 $ 1,509,511 $ 204,109 $ 139,446 Reinsurance 152,057 19,468 — 171,525 22,413 15,807 Corporate, other and eliminations (1) — 6,757 119,260 126,017 (51,506 ) (37,684 ) Net investment gains — — 53,904 53,904 53,904 35,038 Total $ 1,531,558 $ 133,214 $ 196,185 $ 1,860,957 $ 228,920 $ 152,607 Nine months ended September 30, 2016: Insurance $ 4,206,887 322,779 $ 77,215 $ 4,606,881 $ 604,825 $ 407,346 Reinsurance 466,185 59,244 — 525,429 61,041 42,285 Corporate, other and eliminations (1) — 22,827 338,009 360,836 (190,655 ) (123,610 ) Net investment gains — — 189,394 189,394 189,394 123,106 Total $ 4,673,072 $ 404,850 $ 604,618 $ 5,682,540 $ 664,605 $ 449,127 Nine months ended September 30, 2015: Insurance $ 4,042,159 $ 309,337 $ 72,981 $ 4,424,477 $ 575,748 $ 395,581 Reinsurance 454,453 54,575 — 509,028 69,797 49,134 Corporate, other and eliminations (1) — 21,124 340,267 361,391 (170,226 ) (116,094 ) Net investment gains — — 100,505 100,505 100,505 65,328 Total $ 4,496,612 $ 385,036 $ 513,753 $ 5,395,401 $ 575,824 $ 393,949 ________ (1) Corporate, other and eliminations represent corporate revenues and expenses that are not allocated to business segments. Identifiable Assets (In thousands) September 30, 2016 December 31, 2015 Insurance $ 18,972,237 $ 18,063,730 Reinsurance 2,585,307 2,441,340 Corporate, other and eliminations 1,788,112 1,219,086 Consolidated $ 23,345,656 $ 21,724,156 Net premiums earned by major line of business are as follows: For the Three Months For the Nine Months Ended September 30, Ended September 30, (In thousands) 2016 2015 2016 2015 Insurance: Other liability $ 465,068 $ 418,133 $ 1,331,143 $ 1,216,411 Workers’ compensation 355,604 347,745 1,047,412 1,010,279 Short-tail lines (1) 317,498 327,357 977,138 973,606 Commercial automobile 164,540 170,660 481,249 506,229 Professional liability 128,954 115,606 369,945 335,634 Total Insurance 1,431,664 1,379,501 4,206,887 4,042,159 Reinsurance: Casualty 93,757 103,198 290,373 314,462 Property 60,523 48,859 175,812 139,991 Total Reinsurance 154,280 152,057 466,185 454,453 Total $ 1,585,944 $ 1,531,558 $ 4,673,072 $ 4,496,612 ______________ (1) Short-tail lines include commercial multi-peril (non-liability), inland marine, accident and health, fidelity and surety, boiler and machinery and other lines.

Per Share Data (Tables)

Per Share Data (Tables)	9 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Schedule of Weighted Average Number of Shares [Table Text Block]	The weighted average number of common shares used in the computation of basic and diluted earnings per share was as follows: For the Three Months For the Nine Months Ended September 30, Ended September 30, (In thousands) 2016 2015 2016 2015 Basic 122,562 123,163 122,652 124,294 Diluted 128,556 128,947 128,501 130,563

Acquistions Acquisitions (Table

Acquistions Acquisitions (Tables)	9 Months Ended
	Sep. 30, 2016
Business Acquisition [Line Items]
Summary of fair value of net assets acquired and liabilities assumed	The following table summarizes the initial estimated fair value of net assets acquired and liabilities assumed for the business combinations completed in 2016: (In thousands) 2016 Investments $ 6,764 Cash and cash equivalents 4,266 Real estate, furniture and equipment 701 Goodwill and other intangibles assets 45,782 Premiums and service fees receivable 3,845 Other assets 5,213 Total assets acquired 66,571 Other liabilities assumed (4,931 ) Noncontrolling interest (3,850 ) Net assets acquired $ 57,790

Statements of Comprehensive I31

Statements of Comprehensive Income (Loss) Statements of Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 30, 2015
Equity [Abstract]
Components of changes in accumulated other comprehensive income (loss)	(In thousands) Unrealized Investment Gains (Losses) Currency Translation Adjustments Accumulated Other Comprehensive Income (Loss) As of and for the nine months ended September 30, 2015: Changes in AOCI Beginning of period $ 306,199 $ (122,649 ) $ 183,550 Other comprehensive income (loss) before reclassifications (69,078 ) (76,713 ) (145,791 ) Amounts reclassified from AOCI (9,754 ) — (9,754 ) Other comprehensive income (loss) (78,832 ) (76,713 ) (155,545 ) Unrealized investment gain related to non-controlling interest 106 — 106 End of period $ 227,473 $ (199,362 ) $ 28,111 Amounts reclassified from AOCI Pre-tax $ (15,006 ) (1) $ — $ (15,006 ) Tax effect 5,252 (2) — 5,252 After-tax amounts reclassified $ (9,754 ) $ — $ (9,754 ) Other comprehensive income (loss) Pre-tax $ (135,186 ) $ (76,713 ) $ (211,899 ) Tax effect 56,354 56,354 Other comprehensive income (loss) $ (78,832 ) $ (76,713 ) $ (155,545 ) As of and for the three months ended September 30, 2015: Changes in AOCI Beginning of period $ 222,882 $ (136,827 ) $ 86,055 Other comprehensive income (loss) before reclassifications 3,943 (62,535 ) (58,592 ) Amounts reclassified from AOCI 554 — 554 Other comprehensive income (loss) 4,497 (62,535 ) (58,038 ) Unrealized investment gain related to non-controlling interest 94 — 94 End of period $ 227,473 $ (199,362 ) $ 28,111 Amounts reclassified from AOCI Pre-tax $ 852 (1) $ — $ 852 Tax effect (298 ) (2) — (298 ) After-tax amounts reclassified $ 554 $ — $ 554 Other comprehensive income (loss) Pre-tax $ (7,731 ) $ (62,535 ) $ (70,266 ) Tax effect 12,228 — 12,228 Other comprehensive income (loss) $ 4,497 $ (62,535 ) $ (58,038 ) _______________ (1) Net investment (gains) losses in the consolidated statements of income. (2) Income tax expense in the consolidated statements of income.

Investments In Fixed Maturity32

Investments In Fixed Maturity Securities Investments in Fixed Maturity Securities (Tables)	9 Months Ended
	Sep. 30, 2016
Schedule of Marketable Securities [Line Items]
Amortized cost and fair value of fixed maturity securities by contractual maturity	The amortized cost and fair value of fixed maturity securities at September 30, 2016 , by contractual maturity, are shown below. Actual maturities may differ from contractual maturities because certain issuers may have the right to call or prepay obligations. (In thousands) Amortized Cost Fair Value Due in one year or less $ 1,032,042 $ 1,054,113 Due after one year through five years 5,068,197 5,246,081 Due after five years through ten years 3,287,833 3,500,463 Due after ten years 2,462,938 2,553,828 Mortgage-backed securities 1,257,042 1,281,806 Total $ 13,108,052 $ 13,636,291
Debt Securities [Member]
Schedule of Marketable Securities [Line Items]
Schedule of investments in fixed maturity securities	At September 30, 2016 and December 31, 2015 , investments in fixed maturity securities were as follows: (In thousands) Amortized Cost Gross Unrealized Fair Value Carrying Value Gains Losses September 30, 2016 Held to maturity: State and municipal $ 71,608 $ 17,388 $ — $ 88,996 $ 71,608 Residential mortgage-backed 16,569 2,232 — 18,801 16,569 Total held to maturity 88,177 19,620 — 107,797 88,177 Available for sale: U.S. government and government agency 530,541 25,383 (931 ) 554,993 554,993 State and municipal: Special revenue 2,707,492 124,159 (1,767 ) 2,829,884 2,829,884 State general obligation 528,380 33,688 (560 ) 561,508 561,508 Pre-refunded 366,360 31,900 (9 ) 398,251 398,251 Corporate backed 374,355 15,424 (235 ) 389,544 389,544 Local general obligation 350,349 32,193 (14 ) 382,528 382,528 Total state and municipal 4,326,936 237,364 (2,585 ) 4,561,715 4,561,715 Mortgage-backed securities: Residential (1) 1,131,545 27,275 (4,859 ) 1,153,961 1,153,961 Commercial 108,928 1,032 (916 ) 109,044 109,044 Total mortgage-backed securities 1,240,473 28,307 (5,775 ) 1,263,005 1,263,005 Asset-backed 2,265,206 15,729 (12,074 ) 2,268,861 2,268,861 Corporate: Industrial 2,168,312 111,260 (3,692 ) 2,275,880 2,275,880 Financial 1,288,472 52,419 (5,384 ) 1,335,507 1,335,507 Utilities 199,941 11,593 (785 ) 210,749 210,749 Other 90,229 1,816 (13 ) 92,032 92,032 Total corporate 3,746,954 177,088 (9,874 ) 3,914,168 3,914,168 Foreign 909,765 58,477 (2,490 ) 965,752 965,752 Total available for sale 13,019,875 542,348 (33,729 ) 13,528,494 13,528,494 Total investments in fixed maturity securities $ 13,108,052 $ 561,968 $ (33,729 ) $ 13,636,291 $ 13,616,671 (In thousands) Amortized Gross Unrealized Fair Carrying Gains Losses December 31, 2015 Held to maturity: State and municipal $ 77,129 $ 16,246 $ — $ 93,375 $ 77,129 Residential mortgage-backed 19,138 2,207 — 21,345 19,138 Total held to maturity 96,267 18,453 — 114,720 96,267 Available for sale: U.S. government and government agency 645,092 27,660 (2,333 ) 670,419 670,419 State and municipal: Special revenue 2,510,816 102,909 (3,737 ) 2,609,988 2,609,988 State general obligation 583,456 28,068 (2,070 ) 609,454 609,454 Pre-refunded 439,772 32,056 (31 ) 471,797 471,797 Corporate backed 388,904 14,039 (402 ) 402,541 402,541 Local general obligation 342,158 24,270 (29 ) 366,399 366,399 Total state and municipal 4,265,106 201,342 (6,269 ) 4,460,179 4,460,179 Mortgage-backed securities: Residential (1) 1,126,382 18,935 (11,180 ) 1,134,137 1,134,137 Commercial 64,975 875 (128 ) 65,722 65,722 Total mortgage-backed securities 1,191,357 19,810 (11,308 ) 1,199,859 1,199,859 Asset-backed 1,706,694 12,892 (14,414 ) 1,705,172 1,705,172 Corporate: Industrial 1,976,393 75,168 (30,027 ) 2,021,534 2,021,534 Financial 1,153,096 31,744 (11,819 ) 1,173,021 1,173,021 Utilities 192,857 8,321 (2,527 ) 198,651 198,651 Other 81,607 245 (20 ) 81,832 81,832 Total corporate 3,403,953 115,478 (44,393 ) 3,475,038 3,475,038 Foreign 799,839 50,310 (12,689 ) 837,460 837,460 Total available for sale 12,012,041 427,492 (91,406 ) 12,348,127 12,348,127 Total investments in fixed maturity securities $ 12,108,308 $ 445,945 $ (91,406 ) $ 12,462,847 $ 12,444,394 ____________ (1) Gross unrealized losses for residential mortgage-backed securities include $857,252 and $1,269,491 as of September 30, 2016 and December 31, 2015 , respectively, related to the non-credit portion of other-than-temporary impairments (“OTTI”) recognized in accumulated other comprehensive income.

Investments in Equity Securit33

Investments in Equity Securities Investments in Equity Securities (Tables)	9 Months Ended
	Sep. 30, 2016
Equity securities available for sale
Schedule of Available-for-sale Securities [Line Items]
Schedule of Investments in Equity Securities	At September 30, 2016 and December 31, 2015 , investments in equity securities were as follows: (In thousands) Cost Gross Unrealized Fair Value Carrying Value Gains Losses September 30, 2016 Common stocks $ 37,897 $ 215 $ (2,441 ) $ 35,671 $ 35,671 Preferred stocks 125,759 6,573 (9,028 ) 123,304 123,304 Total $ 163,656 $ 6,788 $ (11,469 ) $ 158,975 $ 158,975 December 31, 2015 Common stocks $ 56,462 $ — $ (19,189 ) $ 37,273 $ 37,273 Preferred stocks 108,730 8,216 (3,353 ) 113,593 113,593 Total $ 165,192 $ 8,216 $ (22,542 ) $ 150,866 $ 150,866

Net Investment Income (Tables)

Net Investment Income (Tables)	9 Months Ended
	Sep. 30, 2016
Net Investment Income [Abstract]
Schedule of Net Investment Income	Net investment income consists of the following: For the Three Months For the Nine Months Ended September 30, Ended September 30, (In thousands) 2016 2015 2016 2015 Investment income earned on: Fixed maturity securities, including cash and cash equivalents and loans receivable $ 114,271 $ 104,936 $ 331,448 $ 318,095 Investment funds 25,293 22,926 60,385 50,838 Arbitrage trading account 6,441 2,608 12,883 11,470 Equity securities available for sale 1,069 1,109 3,217 3,513 Real estate 585 4,389 4,552 9,270 Gross investment income 147,659 135,968 412,485 393,186 Investment expense (1,991 ) (2,754 ) (7,635 ) (8,150 ) Net investment income $ 145,668 $ 133,214 $ 404,850 $ 385,036

Investment Funds Investment F35

Investment Funds Investment Funds (Tables)	9 Months Ended
	Sep. 30, 2016
Equity Method Investments and Joint Ventures [Abstract]
Schedule of Net Investment Funds	Investment funds consist of the following: Carrying Value as of Income (Loss) from Investment Funds September 30, December 31, For the Nine Months Ended September 30, (In thousands) 2016 2015 2016 2015 Real estate $ 646,102 $ 580,830 $ 33,028 $ 51,467 Energy 80,900 93,719 7,174 (25,124 ) Hedge equity 71,371 70,580 791 (3,925 ) Other funds 433,327 424,911 19,392 28,420 Total $ 1,231,700 $ 1,170,040 $ 60,385 $ 50,838

Real Estate Real Estate (Tables

Real Estate Real Estate (Tables)	9 Months Ended
	Sep. 30, 2016
Real Estate [Abstract]
Schedule of Real Estate Investments	Investment in real estate represents directly owned property held for investment, as follows: Carrying Value September 30, December 31, (In thousands) 2016 2015 Properties in operation $ 441,795 $ 226,055 Properties under development 666,687 710,312 Total $ 1,108,482 $ 936,367

Loans Receivable Loans Receiv37

Loans Receivable Loans Receivable (Tables)	9 Months Ended
	Sep. 30, 2016
Receivables [Abstract]
Schedule of Loans Receivable	Loans receivable are as follows: (In thousands) September 30, 2016 December 31, 2015 Amortized cost (net of valuation allowance): Real estate loans $ 96,312 $ 200,499 Commercial loans 17,684 72,604 Total $ 113,996 $ 273,103 Fair value: Real estate loans $ 97,296 $ 201,641 Commercial loans 19,187 74,106 Total $ 116,483 $ 275,747 Valuation allowance: Specific $ 1,025 $ — General 2,197 2,094 Total $ 3,222 $ 2,094 For the Three Months Ended September 30, 2016 2015 Increase in valuation allowance $ 467 $ 19 For the Nine Months Ended September 30, 2016 2015 Increase (decrease) in valuation allowance $ 1,128 $ (81 )

Realized And Unrealized Inves38

Realized And Unrealized Investment Gains (Losses) (Tables)	9 Months Ended
	Sep. 30, 2016
Realized and Unrealized Investment Gains (Losses) [Abstract]
Realized and Unrealized Investment Gains (Losses)	Realized and unrealized investment gains (losses) are as follows: For the Three Months Ended September 30, For the Nine Months Ended September 30, (In thousands) 2016 2015 2016 2015 Realized investment gains (losses): Fixed maturity securities: Gains $ 33,798 $ 1,341 $ 66,972 $ 8,178 Losses (1,150 ) (2,171 ) (5,570 ) (2,810 ) Equity securities available for sale 8,441 (21 ) 13,037 9,639 Investment funds (3,788 ) 70,648 (9,041 ) 92,821 Real estate 687 — 5,247 — Other (1) 137,750 (3,378 ) 136,863 5,192 Net realized gains on investments sales 175,738 66,419 207,508 113,020 Other-than-temporary impairments (2) — (12,515 ) (18,114 ) (12,515 ) Net investment gains 175,738 53,904 189,394 100,505 Income tax expense (61,508 ) (18,866 ) (66,288 ) (35,177 ) After-tax net realized investment gains $ 114,230 $ 35,038 $ 123,106 $ 65,328
Unrealized Gain (Loss) on Investments	Change in unrealized investment gains (losses) of available for sale securities: Fixed maturity securities $ (45,388 ) $ 2,449 $ 169,933 $ (102,863 ) Previously impaired fixed maturity securities (1,406 ) 50 413 73 Equity securities available for sale (28,517 ) (2,353 ) 12,433 (15,977 ) Investment funds 3,143 (7,876 ) 16,028 (16,417 ) Total change in unrealized investment gains (losses) (72,168 ) (7,730 ) 198,807 (135,184 ) Income tax benefit (expense) 24,493 12,229 (64,594 ) 56,354 Noncontrolling interests 57 94 66 106 After-tax change in unrealized investment gains (losses) of available for sale securities $ (47,618 ) $ 4,593 $ 134,279 $ (78,724 ) ______________________ (1) Other includes a gain of $ 134.9 million from the sale of Aero Precision Industries, and certain related aviation services business, for the three and nine months ended September 30, 2016. (2) Other than temporary impairments (OTTI) for the nine months ended September 30, 2016 of $18.1 million were related to equity securities available for sale. OTTI for the three and nine months ended September 30, 2015 of $12.5 million were related to equity securities available for sale and fixed maturity securities of $3.5 million and $9.0 million, respectively.

Securities In An Unrealized L39

Securities In An Unrealized Loss Position Securities In An Unrealized Loss Position (Tables)	9 Months Ended
	Sep. 30, 2016
Statement of Financial Position [Abstract]
Securities in an unrealized loss position	The following tables summarize all securities in an unrealized loss position at September 30, 2016 and December 31, 2015 by the length of time those securities have been continuously in an unrealized loss position: Less Than 12 Months 12 Months or Greater Total (In thousands) Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses September 30, 2016 U.S. government and government agency $ 54,550 $ 279 $ 39,092 $ 652 $ 93,642 $ 931 State and municipal 217,215 1,095 138,082 1,490 355,297 2,585 Mortgage-backed securities 251,969 1,851 105,927 3,924 357,896 5,775 Asset-backed securities 918,983 5,718 214,436 6,356 1,133,419 12,074 Corporate 337,940 2,152 98,162 7,722 436,102 9,874 Foreign 52,233 640 30,842 1,850 83,075 2,490 Fixed maturity securities 1,832,890 11,735 626,541 21,994 2,459,431 33,729 Common stocks 18,112 779 8,116 1,662 26,228 2,441 Preferred stocks 46,135 8,199 24,845 829 70,980 9,028 Equity securities available for sale 64,247 8,978 32,961 2,491 97,208 11,469 Total $ 1,897,137 $ 20,713 $ 659,502 $ 24,485 $ 2,556,639 $ 45,198 December 31, 2015 U.S. government and government agency $ 101,660 $ 487 $ 64,500 $ 1,846 $ 166,160 $ 2,333 State and municipal 501,952 4,404 106,681 1,865 608,633 6,269 Mortgage-backed securities 381,986 3,639 184,807 7,669 566,793 11,308 Asset-backed securities 1,091,078 7,703 190,467 6,711 1,281,545 14,414 Corporate 1,232,940 35,406 76,797 8,987 1,309,737 44,393 Foreign 169,190 8,822 19,528 3,867 188,718 12,689 Fixed maturity securities 3,478,806 60,461 642,780 30,945 4,121,586 91,406 Common stocks 18,641 18,005 7,829 1,184 26,470 19,189 Preferred stocks — — 22,320 3,353 22,320 3,353 Equity securities available for sale 18,641 18,005 30,149 4,537 48,790 22,542 Total $ 3,497,447 $ 78,466 $ 672,929 $ 35,482 $ 4,170,376 $ 113,948
Non-Investment Grade Fixed Maturity Securities	Fixed Maturity Securities – A summary of the Company’s non-investment grade fixed maturity securities that were in an unrealized loss position at September 30, 2016 is presented in the table below: ($ in thousands) Number of Securities Aggregate Fair Value Gross Unrealized Loss Corporate 10 $ 27,531 $ 3,045 Mortgage-backed securities 11 23,921 1,229 Foreign government 4 23,001 1,101 Asset-backed securities 5 8,418 405 State and municipal 1 7,007 25 Total 31 $ 89,878 $ 5,805

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets And Liabilities Measured At Fair value, On A Recurring Basis	The following tables present the assets and liabilities measured at fair value on a recurring basis as of September 30, 2016 and December 31, 2015 by level: (In thousands) Total Level 1 Level 2 Level 3 September 30, 2016 Assets: Fixed maturity securities available for sale: U.S. government and government agency $ 554,993 $ — $ 554,993 $ — State and municipal 4,561,715 — 4,561,715 — Mortgage-backed securities 1,263,005 — 1,263,005 — Asset-backed securities 2,268,861 — 2,268,676 185 Corporate 3,914,168 — 3,914,168 — Foreign government 965,752 — 965,752 — Total fixed maturity securities available for sale 13,528,494 — 13,528,309 185 Equity securities available for sale: Common stocks 35,671 27,555 — 8,116 Preferred stocks 123,304 — 119,630 3,674 Total equity securities available for sale 158,975 27,555 119,630 11,790 Arbitrage trading account 602,965 320,280 282,685 — Total $ 14,290,434 $ 347,835 $ 13,930,624 $ 11,975 Liabilities: Trading account securities sold but not yet purchased $ 60,959 $ 60,947 $ 12 $ — December 31, 2015 Assets: Fixed maturity securities available for sale: U.S. government and government agency $ 670,419 $ — $ 670,419 $ — State and municipal 4,460,179 — 4,460,179 — Mortgage-backed securities 1,199,859 — 1,199,859 — Asset-backed securities 1,705,172 — 1,704,973 199 Corporate 3,475,038 — 3,474,884 154 Foreign government 837,460 — 837,460 — Total fixed maturity securities available for sale 12,348,127 — 12,347,774 353 Equity securities available for sale: Common stocks 37,273 29,444 — 7,829 Preferred stocks 113,593 — 109,969 3,624 Total equity securities available for sale 150,866 29,444 109,969 11,453 Arbitrage trading account 376,697 256,914 119,607 176 Total $ 12,875,690 $ 286,358 $ 12,577,350 $ 11,982 Liabilities: Trading account securities sold but not yet purchased $ 37,035 $ 35,559 $ 1,476 $ —
Summarize Changes In Level 3 Assets	The following tables summarize changes in Level 3 assets and liabilities for the nine months ended September 30, 2016 and for the year ended December 31, 2015 : Gains (Losses) Included in: (In thousands) Beginning Balance Earnings (Losses) Other Comprehensive Income (Loss) Impairments Purchases (Sales) Paydowns / Maturities Transfers Ending Balance In / (Out) Nine months ended September 30, 2016: Assets: Fixed maturities securities available for sale: Asset-backed securities $ 199 $ 3 $ 13 $ — $ — $ — $ (30 ) $ — $ 185 Corporate 154 177 — — — (331 ) — — — Total 353 180 13 — — (331 ) (30 ) — 185 Equity securities available for sale: Common stocks 7,829 — (478 ) — 765 — — — 8,116 Preferred stocks 3,624 50 — — — — — — 3,674 Total 11,453 50 (478 ) — 765 — — — 11,790 Arbitrage trading account 176 (176 ) — — — — — — — Total $ 11,982 $ 54 $ (465 ) $ — $ 765 $ (331 ) $ (30 ) $ — $ 11,975 Year ended December 31, 2015: Assets: Fixed maturities securities available for sale: Asset-backed securities $ 20,611 $ 19 $ 191 $ — $ — $ — $ (1,820 ) $ (18,802 ) $ 199 Corporate 154 — — — — — — — 154 Total 20,765 19 191 — — — (1,820 ) (18,802 ) 353 Equity securities available for sale: Common stocks 10,741 — (273 ) (2,331 ) — (308 ) — — 7,829 Preferred stocks 3,713 (89 ) — — — — — — 3,624 Total 14,454 (89 ) (273 ) (2,331 ) — (308 ) — — 11,453 Arbitrage trading account 720 (799 ) — — 72,640 (71,921 ) — (464 ) 176 Total $ 35,939 $ (869 ) $ (82 ) $ (2,331 ) $ 72,640 $ (72,229 ) $ (1,820 ) $ (19,266 ) $ 11,982

Reinsurance (Tables)

Reinsurance (Tables)	9 Months Ended
	Sep. 30, 2016
Reinsurance Disclosures [Abstract]
Reinsurance Financial Information	The following is a summary of reinsurance financial information: For the Three Months For the Nine Months Ended September 30, Ended September 30, (In thousands) 2016 2015 2016 2015 Written premiums: Direct $ 1,643,870 $ 1,601,344 $ 5,061,646 $ 4,852,584 Assumed 224,979 221,237 702,265 633,200 Ceded (261,484 ) (251,544 ) (850,255 ) (795,420 ) Total net premiums written $ 1,607,365 $ 1,571,037 $ 4,913,656 $ 4,690,364 Earned premiums: Direct $ 1,647,033 $ 1,575,624 $ 4,824,768 $ 4,646,343 Assumed 216,758 217,668 635,443 632,362 Ceded (277,847 ) (261,734 ) (787,139 ) (782,093 ) Total net premiums earned $ 1,585,944 $ 1,531,558 $ 4,673,072 $ 4,496,612 Ceded losses and loss expenses incurred $ 213,065 $ 123,765 $ 507,258 $ 374,084 Ceded commissions earned $ 47,315 $ 45,946 $ 143,809 $ 129,766

Fair Value of Financial Instr42

Fair Value of Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Carrying Amounts And Estimated Fair Values Of Financial Instruments	The following table presents the carrying amounts and estimated fair values of the Company’s financial instruments: September 30, 2016 December 31, 2015 (In thousands) Carrying Value Fair Value Carrying Value Fair Value Assets: Fixed maturity securities $ 13,616,671 $ 13,636,291 $ 12,444,394 $ 12,462,847 Equity securities available for sale 158,975 158,975 150,866 150,866 Arbitrage trading account 602,965 602,965 376,697 376,697 Loans receivable 113,996 116,483 273,103 275,747 Cash and cash equivalents 873,064 873,064 763,631 763,631 Trading account receivables from brokers and clearing organizations 185,548 185,548 383,115 383,115 Due from broker — — 1,713 1,713 Liabilities: Due to broker 101,405 101,405 — — Trading account securities sold but not yet purchased 60,959 60,959 37,035 37,035 Subordinated debentures 727,390 779,056 340,320 355,880 Senior notes and other debt 1,762,487 1,997,430 1,844,621 2,029,572

Restricted Stock Units (Tables)

Restricted Stock Units (Tables)	9 Months Ended
	Sep. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary Of Restricted Stock Units Issued	A summary of RSUs issued in the nine months ended September 30, 2016 and 2015 follows: ($ in thousands) Units Fair Value Nine months ended September 30, 2016 990,487 $ 57,959 2015 971,457 $ 54,439

Industry Segments (Tables)

Industry Segments (Tables)	9 Months Ended
	Sep. 30, 2016
Segment Reporting [Abstract]
Financial Information Of Company Operating Segments	Revenues (In thousands) Earned Premiums Investment Income Other Total Pre-Tax Income (Loss) Net Income (Loss) to Common Stockholders Three months ended September 30, 2016 Insurance $ 1,431,664 $ 117,388 $ 22,819 $ 1,571,871 $ 215,649 $ 144,310 Reinsurance 154,280 21,478 — 175,758 22,171 15,167 Corporate, other and eliminations (1) — 6,802 89,560 96,362 (81,941 ) (53,055 ) Net investment gains — — 175,736 175,736 175,736 114,228 Total $ 1,585,944 $ 145,668 $ 288,115 $ 2,019,727 $ 331,615 $ 220,650 Three months ended September 30, 2015 Insurance $ 1,379,501 $ 106,989 $ 23,021 $ 1,509,511 $ 204,109 $ 139,446 Reinsurance 152,057 19,468 — 171,525 22,413 15,807 Corporate, other and eliminations (1) — 6,757 119,260 126,017 (51,506 ) (37,684 ) Net investment gains — — 53,904 53,904 53,904 35,038 Total $ 1,531,558 $ 133,214 $ 196,185 $ 1,860,957 $ 228,920 $ 152,607 Nine months ended September 30, 2016: Insurance $ 4,206,887 322,779 $ 77,215 $ 4,606,881 $ 604,825 $ 407,346 Reinsurance 466,185 59,244 — 525,429 61,041 42,285 Corporate, other and eliminations (1) — 22,827 338,009 360,836 (190,655 ) (123,610 ) Net investment gains — — 189,394 189,394 189,394 123,106 Total $ 4,673,072 $ 404,850 $ 604,618 $ 5,682,540 $ 664,605 $ 449,127 Nine months ended September 30, 2015: Insurance $ 4,042,159 $ 309,337 $ 72,981 $ 4,424,477 $ 575,748 $ 395,581 Reinsurance 454,453 54,575 — 509,028 69,797 49,134 Corporate, other and eliminations (1) — 21,124 340,267 361,391 (170,226 ) (116,094 ) Net investment gains — — 100,505 100,505 100,505 65,328 Total $ 4,496,612 $ 385,036 $ 513,753 $ 5,395,401 $ 575,824 $ 393,949 ________ (1) Corporate, other and eliminations represent corporate revenues and expenses that are not allocated to business segments.
Identifiable Assets By Segment	Identifiable Assets (In thousands) September 30, 2016 December 31, 2015 Insurance $ 18,972,237 $ 18,063,730 Reinsurance 2,585,307 2,441,340 Corporate, other and eliminations 1,788,112 1,219,086 Consolidated $ 23,345,656 $ 21,724,156
Net Premiums Earned By Major Line Of Business	Net premiums earned by major line of business are as follows: For the Three Months For the Nine Months Ended September 30, Ended September 30, (In thousands) 2016 2015 2016 2015 Insurance: Other liability $ 465,068 $ 418,133 $ 1,331,143 $ 1,216,411 Workers’ compensation 355,604 347,745 1,047,412 1,010,279 Short-tail lines (1) 317,498 327,357 977,138 973,606 Commercial automobile 164,540 170,660 481,249 506,229 Professional liability 128,954 115,606 369,945 335,634 Total Insurance 1,431,664 1,379,501 4,206,887 4,042,159 Reinsurance: Casualty 93,757 103,198 290,373 314,462 Property 60,523 48,859 175,812 139,991 Total Reinsurance 154,280 152,057 466,185 454,453 Total $ 1,585,944 $ 1,531,558 $ 4,673,072 $ 4,496,612

General General (Details)

General General (Details)	9 Months Ended
	Sep. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Federal Income Tax Rate	35.00%

Per Share Data (Weighted Averag

Per Share Data (Weighted Average Number of Common Shares Used In the Computation of Basic and Diluted Earnings per Share) (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Abstract]
Basic (shares)	122,562	123,163	122,652	124,294
Diluted (shares)	128,556	128,947	128,501	130,563

Acquistions Acquisitions (Detai

Acquistions Acquisitions (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Goodwill	$ 134,146	$ 153,291
Premiums and fees receivable	1,742,210	1,669,186
Noncontrolling interests	36,059	32,962
Selling and Marketing Expense [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net	$ 6,764
Business Acquisition, Percentage of Voting Interests Acquired	85.00%
Cash and cash equivalents	$ 4,266
Real estate, furniture and equipment	701
Goodwill and other intangibles assets	45,782
Premiums and fees receivable	3,845
Other assets	5,213
Total assets acquired	66,571
Other liabilities assumed	(4,931)
Noncontrolling interests	(3,850)
Net assets acquired	57,790	$ 42,300
Property and Casualty, Commercial Insurance Product Line [Member]
Business Acquisition [Line Items]
Business Acquisition, Transaction Costs	$ 15,500

Acquistions Intangibles (Detail

Acquistions Intangibles (Details)	Sep. 30, 2016
Selling and Marketing Expense [Member]
Business Acquisition [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired	85.00%

Statements of Comprehensive I49

Statements of Comprehensive Income (Loss) Statements of Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning of Period				$ (66,698)
Other comprehensive income (loss)		$ (67,146)	$ (58,038)	56,824	$ (155,545)
Accumulated Other Comprehensive Income (Loss), End of Period		(9,808)		(9,808)
Net realized investment gains		175,738	66,419	207,508	113,020
Income before income taxes		331,615	228,920	664,605	575,824
Income before taxes		606,348	573,541	1,770,450	1,698,169
Tax effect		(110,952)	(76,184)	(214,789)	(181,595)
After-tax amounts reclassified		220,663	152,736	449,816	394,229
Unrealized investment gains, pre-tax		(72,188)	(7,731)	198,808	(135,186)
Unrealized investment gains, tax effect		24,512	12,228	(64,595)	56,354
Unrealized investment gains, after-tax amounts		(47,676)	4,497	134,213	(78,832)
Currency translation adjustment, pre-tax		(19,470)	(62,535)	(77,389)	(76,713)
Currency translation adjustment, tax effect		0	0	0
Change in unrealized currency translation adjustments		(19,470)	(62,535)	(77,389)	(76,713)
Other comprehensive income (loss), pre-tax		(91,658)	(70,266)	121,419	(211,899)
Other comprehensive income (loss), tax effect		24,512	12,228	(64,595)	56,354
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning of Period		362,593	222,882	180,695	306,199
Other comprehensive income (loss) before reclassifications		(20,968)	3,943	170,824	(69,078)
Amounts reclassified from AOCI		(26,708)	554	(36,611)	(9,754)
Other comprehensive income (loss)		(47,676)	4,497	134,213	(78,832)
Unrealized investment gain related to non-controlling interest		57	94	66	106
Accumulated Other Comprehensive Income (Loss), End of Period		314,974	227,473	314,974	227,473
Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning of Period		(305,312)	(136,827)	(247,393)	(122,649)
Other comprehensive income (loss) before reclassifications		(19,470)	(62,535)	(77,389)	(76,713)
Amounts reclassified from AOCI		0	0	0	0
Other comprehensive income (loss)		(19,470)	(62,535)	(77,389)	(76,713)
Unrealized investment gain related to non-controlling interest		0	0	0	0
Accumulated Other Comprehensive Income (Loss), End of Period		(324,782)	(199,362)	(324,782)	(199,362)
Change in unrealized currency translation adjustments				(77,389)	(76,713)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning of Period		57,281	86,055	(66,698)	183,550
Other comprehensive income (loss) before reclassifications		(40,438)	(58,592)	93,435	(145,791)
Amounts reclassified from AOCI		(26,708)	554	(36,611)	(9,754)
Other comprehensive income (loss)		(67,146)	(58,038)	56,824	(155,545)
Unrealized investment gain related to non-controlling interest		57	94	66	106
Accumulated Other Comprehensive Income (Loss), End of Period		(9,808)	28,111	(9,808)	28,111
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Net realized investment gains	[1]	(41,090)	852	(56,325)	(15,006)
Tax effect	[2]	(14,382)	298	(19,714)	(5,252)
After-tax amounts reclassified		(26,708)	554	(36,611)	(9,754)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Income before income taxes		0	0	0	0
Tax effect		0	0	0	0
After-tax amounts reclassified		0	0	0	0
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Income before income taxes		(41,090)	852	(56,325)	(15,006)
Tax effect		14,382	(298)	19,714	5,252
After-tax amounts reclassified		$ (26,708)	$ 554	$ (36,611)	$ (9,754)
[1]	Net investment (gains) losses in the consolidated statements of income.
[2]	Income tax expense in the consolidated statements of income.

Statements of Cash Flow (Detail

Statements of Cash Flow (Details) - USD ($)	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Supplemental Cash Flow Information [Abstract]
Interest payments	$ 124,791,000	$ 124,632,000
Income taxes paid	$ 99,161,000	$ 96,364,000

Investments In Fixed Maturity51

Investments In Fixed Maturity Securities Investments in Fixed Maturity Securities (Investments in fixed maturity securities) (Details) - USD ($)		Sep. 30, 2016		Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Total held to maturity, Amortized Cost		$ 88,177,000		$ 96,267,000
Held to Maturity Securities Accumulated Unrecognized Holding Gain		19,620,000		(18,453,000)
Held to Maturity Securities Accumulated Unrecognized Holding Loss		0		0
Total held to maturity, Fair Value		107,797,000		114,720,000
Total held to maturity, Carrying Value		88,177,000		96,267,000
Total available for sale, Amortized Cost		13,019,875,000		12,012,041,000
Total available for sale, Gross Unrealized Gains		542,348,000		427,492,000
Total available for sale, Gross Unrealized Losses		(33,729,000)		(91,406,000)
Total available for sale, Fair Value		13,528,494,000		12,348,127,000
Total available for sale, Carrying Value		13,528,494,000		12,348,127,000
Total investments in fixed maturity securities, Amortized Value		13,108,052,000		12,108,308,000
Total investments in fixed maturity securities, Gross Unrealized Gains		561,968,000		445,945,000
Total investments in fixed maturity securities, Gross Unrealized Losses		(33,729,000)		(91,406,000)
Total investments in fixed maturity securities, Fair Value		13,636,291,000		12,462,847,000
Total investments in fixed maturity securities, Carrying Value		$ 13,616,671,000		12,444,394,000
Minimum ownership of Common stockholders equity		10.00%
Foreign government
Schedule of Available-for-sale Securities [Line Items]
Total available for sale, Amortized Cost		$ 909,765,000		799,839,000
Total available for sale, Gross Unrealized Gains		58,477,000		50,310,000
Total available for sale, Gross Unrealized Losses		(2,490,000)		(12,689,000)
Total available for sale, Fair Value		965,752,000		837,460,000
Total available for sale, Carrying Value		965,752,000		837,460,000
Commercial Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total available for sale, Amortized Cost		108,928,000		64,975,000
Total available for sale, Gross Unrealized Gains		1,032,000		875,000
Total available for sale, Gross Unrealized Losses		(916,000)		(128,000)
Total available for sale, Fair Value		109,044,000		65,722,000
Total available for sale, Carrying Value		109,044,000		65,722,000
U.S. government and government agency
Schedule of Available-for-sale Securities [Line Items]
Total available for sale, Amortized Cost		530,541,000		645,092,000
Total available for sale, Gross Unrealized Gains		25,383,000		27,660,000
Total available for sale, Gross Unrealized Losses		(931,000)		(2,333,000)
Total available for sale, Fair Value		554,993,000		670,419,000
Total available for sale, Carrying Value		554,993,000		670,419,000
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total available for sale, Amortized Cost		2,707,492,000		2,510,816,000
Total available for sale, Gross Unrealized Gains		124,159,000		102,909,000
Total available for sale, Gross Unrealized Losses		(1,767,000)		(3,737,000)
Total available for sale, Fair Value		2,829,884,000		2,609,988,000
Total available for sale, Carrying Value		2,829,884,000		2,609,988,000
Corporation [Member]
Schedule of Available-for-sale Securities [Line Items]
Total available for sale, Amortized Cost		374,355,000		388,904,000
Total available for sale, Gross Unrealized Gains		15,424,000		14,039,000
Total available for sale, Gross Unrealized Losses		(235,000)		(402,000)
Total available for sale, Fair Value		389,544,000		402,541,000
Total available for sale, Carrying Value		389,544,000		402,541,000
Debt, State Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Total available for sale, Amortized Cost		528,380,000		583,456,000
Total available for sale, Gross Unrealized Gains		33,688,000		28,068,000
Total available for sale, Gross Unrealized Losses		(560,000)		(2,070,000)
Total available for sale, Fair Value		561,508,000		609,454,000
Total available for sale, Carrying Value		561,508,000		609,454,000
Revenue Subject to Refund [Member]
Schedule of Available-for-sale Securities [Line Items]
Total available for sale, Amortized Cost		366,360,000		439,772,000
Total available for sale, Gross Unrealized Gains		31,900,000		32,056,000
Total available for sale, Gross Unrealized Losses		(9,000)		(31,000)
Total available for sale, Fair Value		398,251,000		471,797,000
Total available for sale, Carrying Value		398,251,000		471,797,000
Residential Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total available for sale, Amortized Cost	[1]	1,131,545,000		1,126,382,000
Total available for sale, Gross Unrealized Gains	[1]	27,275,000		18,935,000
Total available for sale, Gross Unrealized Losses	[1]	(4,859,000)		(11,180,000)
Total available for sale, Fair Value		1,153,961,000	[1]	1,134,137,000
Total available for sale, Carrying Value	[1]	1,153,961,000		1,134,137,000
Non-credit portion of other-than-temporary impairments (OTTI)		857,252		1,269,491
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total available for sale, Amortized Cost		3,746,954,000		3,403,953,000
Total available for sale, Gross Unrealized Gains		177,088,000		115,478,000
Total available for sale, Gross Unrealized Losses		(9,874,000)		(44,393,000)
Total available for sale, Fair Value		3,914,168,000		3,475,038,000
Total available for sale, Carrying Value		3,914,168,000		3,475,038,000
State and municipal
Schedule of Available-for-sale Securities [Line Items]
Total available for sale, Amortized Cost		4,326,936,000		4,265,106,000
Total available for sale, Gross Unrealized Gains		237,364,000		201,342,000
Total available for sale, Gross Unrealized Losses		(2,585,000)		(6,269,000)
Total available for sale, Fair Value		4,561,715,000		4,460,179,000
Total available for sale, Carrying Value		4,561,715,000		4,460,179,000
Debt, Local Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Total available for sale, Amortized Cost		350,349,000		342,158,000
Total available for sale, Gross Unrealized Gains		32,193,000		24,270,000
Total available for sale, Gross Unrealized Losses		(14,000)		(29,000)
Total available for sale, Fair Value		382,528,000		366,399,000
Total available for sale, Carrying Value		382,528,000		366,399,000
Mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Total available for sale, Amortized Cost		1,240,473,000		1,191,357,000
Total available for sale, Gross Unrealized Gains		28,307,000		19,810,000
Total available for sale, Gross Unrealized Losses		(5,775,000)		(11,308,000)
Total available for sale, Fair Value		1,263,005,000		1,199,859,000
Total available for sale, Carrying Value		1,263,005,000		1,199,859,000
Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total available for sale, Amortized Cost		2,265,206,000		1,706,694,000
Total available for sale, Gross Unrealized Gains		15,729,000		12,892,000
Total available for sale, Gross Unrealized Losses		(12,074,000)		(14,414,000)
Total available for sale, Fair Value		2,268,861,000		1,705,172,000
Total available for sale, Carrying Value		2,268,861,000		1,705,172,000
Industrial Property [Member]
Schedule of Available-for-sale Securities [Line Items]
Total available for sale, Amortized Cost		2,168,312,000		1,976,393,000
Total available for sale, Gross Unrealized Gains		111,260,000		75,168,000
Total available for sale, Gross Unrealized Losses		(3,692,000)		(30,027,000)
Total available for sale, Fair Value		2,275,880,000		2,021,534,000
Total available for sale, Carrying Value		2,275,880,000		2,021,534,000
Domestic Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total available for sale, Amortized Cost		1,288,472,000		1,153,096,000
Total available for sale, Gross Unrealized Gains		52,419,000		31,744,000
Total available for sale, Gross Unrealized Losses		(5,384,000)		(11,819,000)
Total available for sale, Fair Value		1,335,507,000		1,173,021,000
Total available for sale, Carrying Value		1,335,507,000		1,173,021,000
Public Utility, Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Total available for sale, Amortized Cost		199,941,000		192,857,000
Total available for sale, Gross Unrealized Gains		11,593,000		8,321,000
Total available for sale, Gross Unrealized Losses		(785,000)		(2,527,000)
Total available for sale, Fair Value		210,749,000		198,651,000
Total available for sale, Carrying Value		210,749,000		198,651,000
Other Security Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Total available for sale, Amortized Cost		90,229,000		81,607,000
Total available for sale, Gross Unrealized Gains		1,816,000		245,000
Total available for sale, Gross Unrealized Losses		(13,000)		(20,000)
Total available for sale, Fair Value		92,032,000		81,832,000
Total available for sale, Carrying Value		92,032,000		81,832,000
State and municipal
Schedule of Available-for-sale Securities [Line Items]
Total held to maturity, Amortized Cost		71,608,000		77,129,000
Held to Maturity Securities Accumulated Unrecognized Holding Gain		17,388,000		(16,246,000)
Held to Maturity Securities Accumulated Unrecognized Holding Loss		0		0
Total held to maturity, Fair Value		88,996,000		93,375,000
Total held to maturity, Carrying Value		71,608,000		77,129,000
Residential Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total held to maturity, Amortized Cost		16,569,000		19,138,000
Held to Maturity Securities Accumulated Unrecognized Holding Gain		2,232,000		(2,207,000)
Held to Maturity Securities Accumulated Unrecognized Holding Loss		0		0
Total held to maturity, Fair Value		18,801,000		21,345,000
Total held to maturity, Carrying Value		$ 16,569,000		$ 19,138,000
[1]	Gross unrealized losses for residential mortgage-backed securities include $857,252 and $1,269,491 as of September 30, 2016 and December 31, 2015, respectively, related to the non-credit portion of other-than-temporary impairments (“OTTI”) recognized in accumulated other comprehensive income.

Investments In Fixed Maturity52

Investments In Fixed Maturity Securities Investments in Fixed Maturity Securities (Amortized cost and fair value of fixed maturity securities) (Details) - USD ($) $ in Thousands		Sep. 30, 2016		Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment		$ 88,177		$ 96,267
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain		(19,620)		18,453
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss		0		0
Held-to-maturity Securities, Fair Value		107,797		114,720
Held-to-maturity Securities		88,177		96,267
Available-for-sale Debt Securities, Amortized Cost Basis		13,019,875		12,012,041
Available For Sale Securities Debt Securities Gross Unrealized Gain		542,348		427,492
Available For Sale Securities Debt Securities Gross Unrealized Losses		(33,729)		(91,406)
Available For Sale Securities Debt Securities Fair Value		13,528,494		12,348,127
Available-for-sale Securities, Debt Securities		13,528,494		12,348,127
Marketable Securities Fixed Maturities Gross Unrealized Gains		561,968		445,945
Fixed maturity securities		13,616,671		12,444,394
Marketable Securities Fixed Maturities Gross Unrealized Losses		33,729		91,406
Amortized Cost, Due in one year or less		1,032,042
Amortized Cost, Due after one year through five years		5,068,197
Amortized Cost, Due after five years through ten years		3,287,833
Amortized Cost, Due after ten years		2,462,938
Amortized Cost, Mortgaged-backed securities		1,257,042
Total investments in fixed maturity securities, Amortized Value		13,108,052		12,108,308
Fair Value, Due in one year or less		1,054,113
Fair Value, Due after one year through five years		5,246,081
Fair Value, Due after five years through ten years		3,500,463
Fair Value, Due after ten years		2,553,828
Fair Value, Mortgage-backed securities		1,281,806
Total investments in fixed maturity securities, Fair Value		13,636,291		12,462,847
Foreign government
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis		909,765		799,839
Available For Sale Securities Debt Securities Gross Unrealized Gain		58,477		50,310
Available For Sale Securities Debt Securities Gross Unrealized Losses		(2,490)		(12,689)
Available For Sale Securities Debt Securities Fair Value		965,752		837,460
Available-for-sale Securities, Debt Securities		965,752		837,460
Commercial Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis		108,928		64,975
Available For Sale Securities Debt Securities Gross Unrealized Gain		1,032		875
Available For Sale Securities Debt Securities Gross Unrealized Losses		(916)		(128)
Available For Sale Securities Debt Securities Fair Value		109,044		65,722
Available-for-sale Securities, Debt Securities		109,044		65,722
Residential Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	[1]	1,131,545		1,126,382
Available For Sale Securities Debt Securities Gross Unrealized Gain	[1]	27,275		18,935
Available For Sale Securities Debt Securities Gross Unrealized Losses	[1]	(4,859)		(11,180)
Available For Sale Securities Debt Securities Fair Value		1,153,961	[1]	1,134,137
Available-for-sale Securities, Debt Securities	[1]	1,153,961		1,134,137
State and municipal
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis		4,326,936		4,265,106
Available For Sale Securities Debt Securities Gross Unrealized Gain		237,364		201,342
Available For Sale Securities Debt Securities Gross Unrealized Losses		(2,585)		(6,269)
Available For Sale Securities Debt Securities Fair Value		4,561,715		4,460,179
Available-for-sale Securities, Debt Securities		4,561,715		4,460,179
U.S. government and government agency
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis		530,541		645,092
Available For Sale Securities Debt Securities Gross Unrealized Gain		25,383		27,660
Available For Sale Securities Debt Securities Gross Unrealized Losses		(931)		(2,333)
Available For Sale Securities Debt Securities Fair Value		554,993		670,419
Available-for-sale Securities, Debt Securities		554,993		670,419
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis		2,707,492		2,510,816
Available For Sale Securities Debt Securities Gross Unrealized Gain		124,159		102,909
Available For Sale Securities Debt Securities Gross Unrealized Losses		(1,767)		(3,737)
Available For Sale Securities Debt Securities Fair Value		2,829,884		2,609,988
Available-for-sale Securities, Debt Securities		2,829,884		2,609,988
Debt, State Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis		528,380		583,456
Available For Sale Securities Debt Securities Gross Unrealized Gain		33,688		28,068
Available For Sale Securities Debt Securities Gross Unrealized Losses		(560)		(2,070)
Available For Sale Securities Debt Securities Fair Value		561,508		609,454
Available-for-sale Securities, Debt Securities		561,508		609,454
Revenue Subject to Refund [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis		366,360		439,772
Available For Sale Securities Debt Securities Gross Unrealized Gain		31,900		32,056
Available For Sale Securities Debt Securities Gross Unrealized Losses		(9)		(31)
Available For Sale Securities Debt Securities Fair Value		398,251		471,797
Available-for-sale Securities, Debt Securities		398,251		471,797
Corporation [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis		374,355		388,904
Available For Sale Securities Debt Securities Gross Unrealized Gain		15,424		14,039
Available For Sale Securities Debt Securities Gross Unrealized Losses		(235)		(402)
Available For Sale Securities Debt Securities Fair Value		389,544		402,541
Available-for-sale Securities, Debt Securities		389,544		402,541
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis		3,746,954		3,403,953
Available For Sale Securities Debt Securities Gross Unrealized Gain		177,088		115,478
Available For Sale Securities Debt Securities Gross Unrealized Losses		(9,874)		(44,393)
Available For Sale Securities Debt Securities Fair Value		3,914,168		3,475,038
Available-for-sale Securities, Debt Securities		3,914,168		3,475,038
Mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis		1,240,473		1,191,357
Available For Sale Securities Debt Securities Gross Unrealized Gain		28,307		19,810
Available For Sale Securities Debt Securities Gross Unrealized Losses		(5,775)		(11,308)
Available For Sale Securities Debt Securities Fair Value		1,263,005		1,199,859
Available-for-sale Securities, Debt Securities		1,263,005		1,199,859
Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis		2,265,206		1,706,694
Available For Sale Securities Debt Securities Gross Unrealized Gain		15,729		12,892
Available For Sale Securities Debt Securities Gross Unrealized Losses		(12,074)		(14,414)
Available For Sale Securities Debt Securities Fair Value		2,268,861		1,705,172
Available-for-sale Securities, Debt Securities		2,268,861		1,705,172
Industrial Property [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis		2,168,312		1,976,393
Available For Sale Securities Debt Securities Gross Unrealized Gain		111,260		75,168
Available For Sale Securities Debt Securities Gross Unrealized Losses		(3,692)		(30,027)
Available For Sale Securities Debt Securities Fair Value		2,275,880		2,021,534
Available-for-sale Securities, Debt Securities		2,275,880		2,021,534
Domestic Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis		1,288,472		1,153,096
Available For Sale Securities Debt Securities Gross Unrealized Gain		52,419		31,744
Available For Sale Securities Debt Securities Gross Unrealized Losses		(5,384)		(11,819)
Available For Sale Securities Debt Securities Fair Value		1,335,507		1,173,021
Available-for-sale Securities, Debt Securities		1,335,507		1,173,021
Public Utility, Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis		199,941		192,857
Available For Sale Securities Debt Securities Gross Unrealized Gain		11,593		8,321
Available For Sale Securities Debt Securities Gross Unrealized Losses		(785)		(2,527)
Available For Sale Securities Debt Securities Fair Value		210,749		198,651
Available-for-sale Securities, Debt Securities		210,749		198,651
Other Security Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis		90,229		81,607
Available For Sale Securities Debt Securities Gross Unrealized Gain		1,816		245
Available For Sale Securities Debt Securities Gross Unrealized Losses		(13)		(20)
Available For Sale Securities Debt Securities Fair Value		92,032		81,832
Available-for-sale Securities, Debt Securities		92,032		81,832
State and municipal
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment		71,608		77,129
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain		(17,388)		16,246
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss		0		0
Held-to-maturity Securities, Fair Value		88,996		93,375
Held-to-maturity Securities		71,608		77,129
Residential Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment		16,569		19,138
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain		(2,232)		2,207
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss		0		0
Held-to-maturity Securities, Fair Value		18,801		21,345
Held-to-maturity Securities		$ 16,569		$ 19,138
[1]	Gross unrealized losses for residential mortgage-backed securities include $857,252 and $1,269,491 as of September 30, 2016 and December 31, 2015, respectively, related to the non-credit portion of other-than-temporary impairments (“OTTI”) recognized in accumulated other comprehensive income.

Investments in Equity Securit53

Investments in Equity Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Cost	$ 163,656	$ 165,192
Gross Unrealized, Gains	6,788	8,216
Gross Unrealized, Losses	(11,469)	(22,542)
Carrying and fair value of equity securities	158,975	150,866
Common stocks
Schedule of Available-for-sale Securities [Line Items]
Cost	37,897	56,462
Gross Unrealized, Gains	215	0
Gross Unrealized, Losses	(2,441)	(19,189)
Carrying and fair value of equity securities	35,671	37,273
Preferred stocks
Schedule of Available-for-sale Securities [Line Items]
Cost	125,759	108,730
Gross Unrealized, Gains	6,573	8,216
Gross Unrealized, Losses	(9,028)	(3,353)
Carrying and fair value of equity securities	$ 123,304	$ 113,593

Arbitrage Trading Account (Deta

Arbitrage Trading Account (Details) - Options Held [Member] $ in Millions	Sep. 30, 2016USD ($)
Short [Member]
Derivative [Line Items]
Derivative, Fair Value, Net	$ 0.7
Derivative, Notional Amount	103.6
Long [Member]
Derivative [Line Items]
Derivative, Fair Value, Net	1.2
Derivative, Notional Amount	$ 53.9

Net Investment Income Net Inv55

Net Investment Income Net Investment Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Net Investment Income [Line Items]
Investment income	$ 147,659	$ 135,968	$ 412,485	$ 393,186
Investment expense	(1,991)	(2,754)	(7,635)	(8,150)
Net investment income	145,668	133,214	404,850	385,036
Fixed maturity securities, including cash and cash equivalents and loans receivable
Net Investment Income [Line Items]
Investment income	114,271	104,936	331,448	318,095
Investment funds
Net Investment Income [Line Items]
Investment income	25,293	22,926	60,385	50,838
Arbitrage trading account
Net Investment Income [Line Items]
Investment income	6,441	2,608	12,883	11,470
Equity securities available for sale
Net Investment Income [Line Items]
Investment income	1,069	1,109	3,217	3,513
Real estate
Net Investment Income [Line Items]
Investment income	$ 585	$ 4,389	$ 4,552	$ 9,270

Investment Funds Investment F56

Investment Funds Investment Funds (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	21.00%
Investment funds	$ 1,231,700		$ 1,170,040
Income (Loss) from Investment Funds	60,385	$ 50,838
Alternative Investments, Fair Value Disclosure	453,000
Real estate
Schedule of Equity Method Investments [Line Items]
Investment funds	646,102		580,830
Income (Loss) from Investment Funds	33,028
Wholly Owned Properties [Member]
Schedule of Equity Method Investments [Line Items]
Income (Loss) from Investment Funds		51,467
Energy
Schedule of Equity Method Investments [Line Items]
Investment funds	80,900		93,719
Income (Loss) from Investment Funds	7,174	(25,124)
Hedge equity
Schedule of Equity Method Investments [Line Items]
Investment funds	71,371		70,580
Income (Loss) from Investment Funds	791	(3,925)
Other funds
Schedule of Equity Method Investments [Line Items]
Investment funds	433,327		$ 424,911
Income (Loss) from Investment Funds	19,392	$ 28,420
Equity Method Investee [Member]
Schedule of Equity Method Investments [Line Items]
Investment funds	$ 53,100

Real Estate Real Estate (Detail

Real Estate Real Estate (Details) - USD ($)	Sep. 30, 2016	Dec. 31, 2015
Real Estate [Abstract]
Properties in operation	$ 441,795,000	$ 226,055,000
Properties under development	666,687,000	710,312,000
Total	1,108,482,000	936,367,000
Real Estate Investment Property, Accumulated Depreciation	$ 13,345,000	$ 9,073,000

Real Estate Real Estate (Deta58

Real Estate Real Estate (Details 1) - USD ($)	3 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Real Estate [Abstract]
Accumulated depreciation and amortization on properties	$ 13,345,000		$ 9,073,000
Real estate depreciation expense	4,117,000	$ 5,991,000
Operating Leases, Future Minimum Payments Receivable, Remainder of Fiscal Year	2,982,866
Lease future minimum payments Current	16,900,586
Operating Leases, Future Minimum Payments Receivable, in Two Years	22,572,465
Lease future minimum payments 2017	20,707,015
Future Minimum Payments 2018	19,471,136
Lease future minimum payments 2019	19,649,571
Lease future minimum payments there after	$ 411,667,096

Loans Receivable (Details)

Loans Receivable (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	$ 9,100		$ 9,100		$ 3,100
Loans and Leases Receivable, Gross	113,996		113,996		273,103
Loans receivable	116,483		116,483		275,747
Valuation allowance, specific	1,025		1,025		0
Valuation allowance, general	2,197		2,197		2,094
Valuation allowance of loans receivable	3,222		3,222		2,094
Decrease in valuation allowance	467	$ 19	1,128	$ (81)
Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	96,312		96,312		200,499
Loans receivable	97,296		97,296		201,641
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	17,684		17,684		72,604
Loans receivable	$ 19,187		$ 19,187		$ 74,106

Realized And Unrealized Inves60

Realized And Unrealized Investment Gains Realized and Unrealized Investment Gains (Loss) (Realized and unrealized investmetns gains(losses)) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Investments, Debt and Equity Securities [Abstract]
Fixed maturity securities, gains	$ 33,798	$ 1,341	$ 66,972	$ 8,178
Fixed maturity securities, losses	(1,150)	(2,171)	(5,570)	(2,810)
Equity securities available for sale	8,441	(21)	13,037	9,639
Investment funds	(3,788)	70,648	(9,041)	92,821
Real Estate Realized Gain (Loss) on Disposal	687	0	5,247	0
Other (1)	137,750	(3,378)	136,863	5,192
Realized Gain (Loss) on Investments, Including Equity Method Investments, Excluding Other than Temporary Impairments and Allowances	175,738	66,419	207,508	113,020
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	0	(12,515)	(18,114)	(12,515)
Gain (Loss) on Investments	175,738	53,904	189,394	100,505
Net investment gains	175,736	53,904	189,394	100,505
Income tax expense	(61,508)	(18,866)	(66,288)	(35,177)
After-tax net realized investment gains	$ 114,230	$ 35,038	$ 123,106	$ 65,328

Realized and Unrealized Inves61

Realized and Unrealized Investment Gains (Losses) (Change in Unrealized Gains (Losses) of Available For Sales Securities) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Realized and Unrealized Investment Gains Losses [Line Items]
pre tax realized gain from sale of wholly owned non insurance business	$ 253,100		$ 135,000
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	0	$ 12,515	18,114	$ 12,515
Change in unrealized gains (losses) before income taxes and noncontrolling interests	(72,168)	(7,730)	198,807	(135,184)
Income tax benefit (expense)	24,493	12,229	(64,594)	56,354
Noncontrolling interests	57	94	66	106
Total change in unrealized gains	(47,618)	4,593	134,279	(78,724)
Proceeds from Divestiture of Businesses	118,200
Debt Securities [Member]
Realized and Unrealized Investment Gains Losses [Line Items]
Change in unrealized gains (losses) before income taxes and noncontrolling interests	(45,388)	2,449	169,933	(102,863)
Debt Securities Previously Impaired [Member]
Realized and Unrealized Investment Gains Losses [Line Items]
Change in unrealized gains (losses) before income taxes and noncontrolling interests	(1,406)	50	413	73
Equity securities available for sale
Realized and Unrealized Investment Gains Losses [Line Items]
Change in unrealized gains (losses) before income taxes and noncontrolling interests	(28,517)	(2,353)	12,433	(15,977)
Investment funds
Realized and Unrealized Investment Gains Losses [Line Items]
Change in unrealized gains (losses) before income taxes and noncontrolling interests	$ 3,143	$ (7,876)	$ 16,028	$ (16,417)

Securities In An Unrealized L62

Securities In An Unrealized Loss Position Securities in an Unrealized Loss Position (Securities in an Unrealized Loss Position) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	$ 1,897,137	$ 3,497,447
Gross Unrealized Losses, Less than 12 Months	20,713	78,466
Fair Value, 12 Months or Greater	659,502	672,929
Gross Unrealized Losses, 12 Months or Greater	24,485	35,482
Fair Value, Total	2,556,639	4,170,376
Gross Unrealized Losses, Total	45,198	113,948
U.S. government and government agency
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	54,550	101,660
Gross Unrealized Losses, Less than 12 Months	279	487
Fair Value, 12 Months or Greater	39,092	64,500
Gross Unrealized Losses, 12 Months or Greater	652	1,846
Fair Value, Total	93,642	166,160
Gross Unrealized Losses, Total	931	2,333
State and municipal
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	217,215	501,952
Gross Unrealized Losses, Less than 12 Months	1,095	4,404
Fair Value, 12 Months or Greater	138,082	106,681
Gross Unrealized Losses, 12 Months or Greater	1,490	1,865
Fair Value, Total	355,297	608,633
Gross Unrealized Losses, Total	2,585	6,269
Mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	251,969	381,986
Gross Unrealized Losses, Less than 12 Months	1,851	3,639
Fair Value, 12 Months or Greater	105,927	184,807
Gross Unrealized Losses, 12 Months or Greater	3,924	7,669
Fair Value, Total	357,896	566,793
Gross Unrealized Losses, Total	5,775	11,308
Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	918,983	1,091,078
Gross Unrealized Losses, Less than 12 Months	5,718	7,703
Fair Value, 12 Months or Greater	214,436	190,467
Gross Unrealized Losses, 12 Months or Greater	6,356	6,711
Fair Value, Total	1,133,419	1,281,545
Gross Unrealized Losses, Total	12,074	14,414
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	337,940	1,232,940
Gross Unrealized Losses, Less than 12 Months	2,152	35,406
Fair Value, 12 Months or Greater	98,162	76,797
Gross Unrealized Losses, 12 Months or Greater	7,722	8,987
Fair Value, Total	436,102	1,309,737
Gross Unrealized Losses, Total	9,874	44,393
Foreign government
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	52,233	169,190
Gross Unrealized Losses, Less than 12 Months	640	8,822
Fair Value, 12 Months or Greater	30,842	19,528
Gross Unrealized Losses, 12 Months or Greater	1,850	3,867
Fair Value, Total	83,075	188,718
Gross Unrealized Losses, Total	2,490	12,689
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	1,832,890	3,478,806
Gross Unrealized Losses, Less than 12 Months	11,735	60,461
Fair Value, 12 Months or Greater	626,541	642,780
Gross Unrealized Losses, 12 Months or Greater	21,994	30,945
Fair Value, Total	2,459,431	4,121,586
Gross Unrealized Losses, Total	33,729	91,406
Preferred stocks
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	46,135	0
Gross Unrealized Losses, Less than 12 Months	8,199	0
Fair Value, 12 Months or Greater	24,845	22,320
Gross Unrealized Losses, 12 Months or Greater	829	3,353
Fair Value, Total	70,980	22,320
Gross Unrealized Losses, Total	9,028	3,353
Equity securities available for sale
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	64,247	18,641
Gross Unrealized Losses, Less than 12 Months	8,978	18,005
Fair Value, 12 Months or Greater	32,961	30,149
Gross Unrealized Losses, 12 Months or Greater	2,491	4,537
Fair Value, Total	97,208	48,790
Gross Unrealized Losses, Total	11,469	22,542
Common stocks
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	18,112	18,641
Gross Unrealized Losses, Less than 12 Months	779	18,005
Fair Value, 12 Months or Greater	8,116	7,829
Gross Unrealized Losses, 12 Months or Greater	1,662	1,184
Fair Value, Total	26,228	26,470
Gross Unrealized Losses, Total	2,441	$ 19,189
Noninvestment Grade Investments at Loss Less than 5 Million [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Total	89,878
Noninvestment Grade Investments at Loss Less than 5 Million [Member] | Mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Total	23,921
Noninvestment Grade Investments at Loss Less than 5 Million [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Total	$ 27,531

Securities In An Unrealized L63

Securities In An Unrealized Loss Position Non-Investment Grade Fixed Maturity Securities (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2016USD ($)sharesposition	Dec. 31, 2015USD ($)
Schedule of Available-for-sale Securities [Line Items]
Aggregate fair value of securities in a continuous unrealized loss position	$ 2,556,639	$ 4,170,376
Available For Sale Equity Securities Gross Unrealized Gains	6,788	8,216
Available For Sale Securities Continuous Unrealized Loss Position Aggregate Losses Accumulated In AOCI	45,198	113,948
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Aggregate fair value of securities in a continuous unrealized loss position	2,459,431	4,121,586
Available For Sale Securities Continuous Unrealized Loss Position Aggregate Losses Accumulated In AOCI	33,729	91,406
Preferred stocks
Schedule of Available-for-sale Securities [Line Items]
Aggregate fair value of securities in a continuous unrealized loss position	70,980	22,320
Available For Sale Equity Securities Gross Unrealized Gains	6,573	8,216
Available For Sale Securities Continuous Unrealized Loss Position Aggregate Losses Accumulated In AOCI	9,028	3,353
Common stocks
Schedule of Available-for-sale Securities [Line Items]
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities	26,000
Aggregate fair value of securities in a continuous unrealized loss position	26,228	26,470
Available For Sale Equity Securities Gross Unrealized Gains	215	0
Available For Sale Securities Continuous Unrealized Loss Position Aggregate Losses Accumulated In AOCI	2,441	19,189
Mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Aggregate fair value of securities in a continuous unrealized loss position	357,896	566,793
Available For Sale Securities Continuous Unrealized Loss Position Aggregate Losses Accumulated In AOCI	5,775	11,308
Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Aggregate fair value of securities in a continuous unrealized loss position	1,133,419	1,281,545
Available For Sale Securities Continuous Unrealized Loss Position Aggregate Losses Accumulated In AOCI	12,074	14,414
State and municipal
Schedule of Available-for-sale Securities [Line Items]
Aggregate fair value of securities in a continuous unrealized loss position	355,297	608,633
Available For Sale Securities Continuous Unrealized Loss Position Aggregate Losses Accumulated In AOCI	2,585	6,269
Foreign government
Schedule of Available-for-sale Securities [Line Items]
Aggregate fair value of securities in a continuous unrealized loss position	83,075	188,718
Available For Sale Securities Continuous Unrealized Loss Position Aggregate Losses Accumulated In AOCI	2,490	12,689
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Aggregate fair value of securities in a continuous unrealized loss position	436,102	1,309,737
Available For Sale Securities Continuous Unrealized Loss Position Aggregate Losses Accumulated In AOCI	$ 9,874	$ 44,393
Noninvestment Grade Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of Securities | shares	3
Noninvestment Grade Investments at Loss Less than 5 Million [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of Securities	31
Aggregate fair value of securities in a continuous unrealized loss position	$ 89,878
Gross Unrealized Loss	$ 5,805
Noninvestment Grade Investments at Loss Less than 5 Million [Member] | Mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Number of Securities	11
Aggregate fair value of securities in a continuous unrealized loss position	$ 23,921
Gross Unrealized Loss	$ 1,229
Noninvestment Grade Investments at Loss Less than 5 Million [Member] | Foreign Government Debt [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of Securities	4
Aggregate fair value of securities in a continuous unrealized loss position	$ 23,001
Gross Unrealized Loss	$ 1,101
Noninvestment Grade Investments at Loss Less than 5 Million [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of Securities	10
Aggregate fair value of securities in a continuous unrealized loss position	$ 27,531
Gross Unrealized Loss	3,045
Common stocks
Schedule of Available-for-sale Securities [Line Items]
Available For Sale Equity Securities Gross Unrealized Gains	$ 2,000
Noninvestment Grade Investments at Loss Less than 5 Million [Member] | Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of Securities | position	5
Aggregate fair value of securities in a continuous unrealized loss position	$ 8,418
Gross Unrealized Loss	$ 405

Securities In An Unrealized L64

Securities In An Unrealized Loss Position Securities In An Unrealized Loss Position (Narrative) (Details) $ in Thousands	Sep. 30, 2016USD ($)shares	Dec. 31, 2015USD ($)
Schedule of Available-for-sale Securities [Line Items]
Aggregate fair value of securities in a continuous unrealized loss position	$ 2,556,639	$ 4,170,376
Gross Unrealized Losses	45,198	113,948
Available For Sale Equity Securities Gross Unrealized Gains	6,788	8,216
Loans and Leases Receivable, Other, Allowance	$ 3,000	2,000
Noninvestment Grade Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of Securities | shares	3
Preferred stocks
Schedule of Available-for-sale Securities [Line Items]
Aggregate fair value of securities in a continuous unrealized loss position	$ 70,980	22,320
Gross Unrealized Losses	9,028	3,353
Available For Sale Equity Securities Gross Unrealized Gains	6,573	8,216
Common stocks
Schedule of Available-for-sale Securities [Line Items]
Aggregate fair value of securities in a continuous unrealized loss position	26,228	26,470
Gross Unrealized Losses	2,441	19,189
Available For Sale Equity Securities Gross Unrealized Gains	215	$ 0
Common stocks
Schedule of Available-for-sale Securities [Line Items]
Available For Sale Equity Securities Gross Unrealized Gains	$ 2,000

Fair Value Measurements (Assets

Fair Value Measurements (Assets and Liabilities Measured At Fair Value, On a Recurring Basis) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	$ 13,528,494	$ 12,348,127
Loans receivable	158,975	150,866
Arbitrage trading account	602,965	376,697
Fair Value, Measurements, Recurring [Member]
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	13,528,494	12,348,127
Loans receivable	158,975	150,866
Assets, fair value disclosure	14,290,434	12,875,690
Arbitrage trading account	602,965	376,697
Securities sold but not yet purchased	60,959	37,035
Fair Value, Measurements, Recurring [Member] | U.S. government and government agency
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	554,993	670,419
Fair Value, Measurements, Recurring [Member] | State and municipal
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	4,561,715	4,460,179
Fair Value, Measurements, Recurring [Member] | Mortgage-backed securities
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	1,263,005	1,199,859
Fair Value, Measurements, Recurring [Member] | Asset-backed Securities [Member]
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	2,268,861	1,705,172
Fair Value, Measurements, Recurring [Member] | Corporate
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	3,914,168	3,475,038
Fair Value, Measurements, Recurring [Member] | Foreign government
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	965,752	837,460
Fair Value, Measurements, Recurring [Member] | Common stocks
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Loans receivable	35,671	37,273
Fair Value, Measurements, Recurring [Member] | Preferred stocks
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Loans receivable	123,304	113,593
Level 1 | Fair Value, Measurements, Recurring [Member]
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	0	0
Loans receivable	27,555	29,444
Assets, fair value disclosure	347,835	286,358
Arbitrage trading account	320,280	256,914
Securities sold but not yet purchased	60,947	35,559
Level 1 | Fair Value, Measurements, Recurring [Member] | U.S. government and government agency
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	0	0
Level 1 | Fair Value, Measurements, Recurring [Member] | State and municipal
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	0	0
Level 1 | Fair Value, Measurements, Recurring [Member] | Mortgage-backed securities
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	0	0
Level 1 | Fair Value, Measurements, Recurring [Member] | Asset-backed Securities [Member]
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	0	0
Level 1 | Fair Value, Measurements, Recurring [Member] | Corporate
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	0	0
Level 1 | Fair Value, Measurements, Recurring [Member] | Foreign government
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	0	0
Level 1 | Fair Value, Measurements, Recurring [Member] | Common stocks
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Loans receivable	27,555	29,444
Level 1 | Fair Value, Measurements, Recurring [Member] | Preferred stocks
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Loans receivable	0	0
Level 2 | Fair Value, Measurements, Recurring [Member]
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	13,528,309	12,347,774
Loans receivable	119,630	109,969
Assets, fair value disclosure	13,930,624	12,577,350
Arbitrage trading account	282,685	119,607
Securities sold but not yet purchased	12	1,476
Level 2 | Fair Value, Measurements, Recurring [Member] | U.S. government and government agency
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	554,993	670,419
Level 2 | Fair Value, Measurements, Recurring [Member] | State and municipal
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	4,561,715	4,460,179
Level 2 | Fair Value, Measurements, Recurring [Member] | Mortgage-backed securities
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	1,263,005	1,199,859
Level 2 | Fair Value, Measurements, Recurring [Member] | Asset-backed Securities [Member]
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	2,268,676	1,704,973
Level 2 | Fair Value, Measurements, Recurring [Member] | Corporate
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	3,914,168	3,474,884
Level 2 | Fair Value, Measurements, Recurring [Member] | Foreign government
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	965,752	837,460
Level 2 | Fair Value, Measurements, Recurring [Member] | Common stocks
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Loans receivable	0	0
Level 2 | Fair Value, Measurements, Recurring [Member] | Preferred stocks
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Loans receivable	119,630	109,969
Level 3 | Fair Value, Measurements, Recurring [Member]
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	185	353
Loans receivable	11,790	11,453
Assets, fair value disclosure	11,975	11,982
Arbitrage trading account	0	176
Securities sold but not yet purchased	0	0
Level 3 | Fair Value, Measurements, Recurring [Member] | U.S. government and government agency
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	0	0
Level 3 | Fair Value, Measurements, Recurring [Member] | State and municipal
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	0	0
Level 3 | Fair Value, Measurements, Recurring [Member] | Mortgage-backed securities
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	0	0
Level 3 | Fair Value, Measurements, Recurring [Member] | Asset-backed Securities [Member]
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	185	199
Level 3 | Fair Value, Measurements, Recurring [Member] | Corporate
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	0	154
Level 3 | Fair Value, Measurements, Recurring [Member] | Foreign government
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities	0	0
Level 3 | Fair Value, Measurements, Recurring [Member] | Common stocks
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Loans receivable	8,116	7,829
Level 3 | Fair Value, Measurements, Recurring [Member] | Preferred stocks
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]
Loans receivable	$ 3,674	$ 3,624

Fair Value Measurements Fair 66

Fair Value Measurements Fair Value Measurements (Summarize Changes in Level 3 Assets) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings, Description	0	(2,331)
Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, beginning balance	$ 11,982	$ 35,939
Assets, earnings	54	(869)
Assets, other comprehensive income	(465)	(82)
Assets, purchases	765	72,640
Assets, (sales)	(331)	(72,229)
Assets, maturities	30	1,820
Assets, ending balance	11,975	11,982
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		19,266
Level 3 | Asset-backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, beginning balance	199	20,611
Assets, earnings	3	19
Assets, other comprehensive income	13	191
Assets, purchases	0	0
Assets, (sales)	0	0
Assets, maturities	(30)	(1,820)
Assets, ending balance	185	199
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0	18,802
Impairment of Intangible Assets (Excluding Goodwill)	0	0
Level 3 | Equity securities available for sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, beginning balance	11,453	14,454
Assets, earnings	50	(89)
Assets, other comprehensive income	(478)	(273)
Assets, purchases	765	0
Assets, (sales)	0	(308)
Assets, ending balance	11,790	11,453
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0	0
Level 3 | Preferred stocks
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, beginning balance	3,624	3,713
Assets, earnings	50	(89)
Assets, other comprehensive income	$ 0	$ 0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings, Description	0	0
Assets, purchases	$ 0	$ 0
Assets, (sales)	0	0
Assets, ending balance	3,674	3,624
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0	0
Level 3 | Common stocks
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, beginning balance	7,829	10,741
Assets, earnings	0	0
Assets, other comprehensive income	$ (478)	$ (273)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings, Description	0	(2,331)
Assets, purchases	$ 765	$ 0
Assets, (sales)	0	(308)
Assets, ending balance	8,116	7,829
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0	0
Level 3 | Debt Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, beginning balance	353	20,765
Assets, earnings	180	19
Assets, other comprehensive income	$ 13	$ 191
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings, Description	0	0
Assets, purchases	$ 0	$ 0
Assets, (sales)	(331)	0
Assets, maturities	30	1,820
Assets, ending balance	185	353
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0	18,802
Level 3 | Corporate Debt Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, beginning balance	154	154
Assets, earnings	177	0
Assets, other comprehensive income	$ 0	$ 0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings, Description	0	0
Assets, purchases	$ 0	$ 0
Assets, (sales)	(331)	0
Assets, ending balance	0	154
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0	0
Level 3 | Trading Assets, Excluding Debt and Equity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, beginning balance	176	720
Assets, earnings	(176)	(799)
Assets, other comprehensive income	$ 0	$ 0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings, Description	0	0
Assets, purchases	$ 0	$ 72,640
Assets, (sales)	0	(71,921)
Assets, ending balance	0	176
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	$ 0	$ 464

Reinsurance Reinsurance (Detail

Reinsurance Reinsurance (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Premiums Written
Written premiums, direct	$ 1,643,870	$ 1,601,344	$ 5,061,646	$ 4,852,584
Written premiums, assumed	224,979	221,237	702,265	633,200
Written premiums, ceded	(261,484)	(251,544)	(850,255)	(795,420)
Total net premiums written	1,607,365	1,571,037	4,913,656	4,690,364
Premiums Earned
Earned premiums, direct	1,647,033	1,575,624	4,824,768	4,646,343
Earned premiums, assumed	216,758	217,668	635,443	632,362
Earned premiums, ceded	(277,847)	(261,734)	(787,139)	(782,093)
Net premiums earned	1,585,944	1,531,558	4,673,072	4,496,612
Ceded losses and loss expenses incurred	213,065	123,765	507,258	374,084
Uncollectible reinsurance	1,000		1,000		$ 1,000
Fees and Commissions, Other	$ 47,315	$ 45,946	$ 143,809	$ 129,766

Fair Value of Financial Instr68

Fair Value of Financial Instruments (Carrying Amounts and Estimated Fair Values of Financial Instruments) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Assets:
Equity securities available for sale	$ 602,965	$ 376,697
Loans receivable	116,483	275,747
Fair Value
Assets:
Fixed maturity securities	13,636,291	12,462,847
Equity securities available for sale	158,975	150,866
Equity securities available for sale	602,965	376,697
Loans receivable	116,483	275,747
Cash and cash equivalents	873,064	763,631
Trading account receivables from brokers and clearing organizations	185,548	383,115
Due From Brokers, Fair Value Disclosure	0	1,713
Due from broker fair value	101,405	0
Liabilities:
Trading account securities sold but not yet purchased	60,959	37,035
Subordinated debentures	779,056	355,880
Senior notes and other debt	1,997,430	2,029,572
Carrying Value
Assets:
Fixed maturity securities	13,616,671	12,444,394
Equity securities available for sale	158,975	150,866
Equity securities available for sale	602,965	376,697
Loans receivable	113,996	273,103
Cash and cash equivalents	873,064	763,631
Trading account receivables from brokers and clearing organizations	185,548	383,115
Due From Brokers, Fair Value Disclosure	0	1,713
Due from broker fair value	101,405	0
Liabilities:
Trading account securities sold but not yet purchased	60,959	37,035
Subordinated debentures	727,390	340,320
Senior notes and other debt	$ 1,762,487	$ 1,844,621

Restricted Stock Units (Summary

Restricted Stock Units (Summary of Restricted Stock Units Issued) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Share-Based Compensation Arrangement by Share-based Payment Award [Line Item]
Share based compensation expense	$ 25,000	$ 23,000
Restricted Stock [Member]
Share-Based Compensation Arrangement by Share-based Payment Award [Line Item]
Restricted Stock Units	990,487	971,457,000
Restricted Stock Units, Fair Value	$ 57,959	$ 54,439
Minimum [Member] | Restricted Stock [Member]
Share-Based Compensation Arrangement by Share-based Payment Award [Line Item]
Award vesting period	3 years
Maximum [Member] | Restricted Stock [Member]
Share-Based Compensation Arrangement by Share-based Payment Award [Line Item]
Award vesting period	5 years

Industry Segments (Financial In

Industry Segments (Financial Information of Company Operating Segments) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Earned Premiums		$ 1,585,944	$ 1,531,558	$ 4,673,072	$ 4,496,612
Investment Income and Funds		145,668	133,214	404,850	385,036
Other Revenues		288,115	196,185	604,618	513,753
Total revenues		2,019,727	1,860,957	5,682,540	5,395,401
Pre-Tax Income (Loss)		331,615	228,920	664,605	575,824
Net Income (Loss)		220,650	152,607	449,127	393,949
Net investment gains		175,736	53,904	189,394	100,505
Net investment gains, net of tax		114,228	35,038	123,106	65,328
Intersegment Eliminations and Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Earned Premiums	[1]	0	0	0	0
Investment Income and Funds	[1]	6,802	6,757	22,827	21,124
Other Revenues	[1]	89,560	119,260	338,009	340,267
Total revenues	[1]	96,362	126,017	360,836	361,391
Pre-Tax Income (Loss)	[1]	(81,941)	(51,506)		(170,226)
Net Income (Loss)	[1]	(53,055)	(37,684)	(123,610)	(116,094)
Insurance-Domestic Segment [Member]
Segment Reporting Information [Line Items]
Earned Premiums		1,431,664	1,379,501	4,206,887	4,042,159
Insurance-Domestic Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Earned Premiums		1,431,664	1,379,501	4,206,887	4,042,159
Investment Income and Funds		117,388	106,989	322,779	309,337
Other Revenues		22,819	23,021	77,215	72,981
Total revenues		1,571,871	1,509,511	4,606,881	4,424,477
Pre-Tax Income (Loss)		215,649	204,109	604,825	575,748
Net Income (Loss)		144,310	139,446	407,346	395,581
Insurance-International Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Other Revenues					0
Reinsurance-Global Segment [Member]
Segment Reporting Information [Line Items]
Earned Premiums		154,280	152,057	466,185	454,453
Reinsurance-Global Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Earned Premiums		154,280	152,057	466,185	454,453
Investment Income and Funds		21,478	19,468	59,244	54,575
Other Revenues		0	0	0
Total revenues		175,758	171,525	525,429	509,028
Pre-Tax Income (Loss)		22,171	22,413	61,041	69,797
Net Income (Loss)		15,167	15,807	42,285	49,134
Corporate, Other and Eliminations Segment [Member] | Intersegment Eliminations and Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Pre-Tax Income (Loss)	[1]			(190,655)
Net Investment Gains Segment [Member]
Segment Reporting Information [Line Items]
Earned Premiums		0	0	0
Investment Income and Funds		$ 0	$ 0	$ 0	$ 0
[1]	Corporate, other and eliminations represent corporate revenues and expenses that are not allocated to business segments.

Industry Segments (Identifiable

Industry Segments (Identifiable Assets by Segment) (Details) - USD ($) $ in Thousands		Sep. 30, 2016	Dec. 31, 2015
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated Assets		$ 23,345,656	$ 21,724,156
Operating Segments [Member] | Reinsurance-Global Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated Assets		2,585,307	2,441,340
Operating Segments [Member] | Insurance-Domestic Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated Assets		18,972,237	18,063,730
Intersegment Eliminations and Corporate, Non-Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated Assets	[1]	$ 1,788,112	$ 1,219,086
[1]	Corporate, other and eliminations represent corporate revenues and expenses that are not allocated to business segments.

Industry Segments Industry Segm

Industry Segments Industry Segments (Net Premiums Earned By Major Line of Business) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Revenue from External Customer [Line Items]
Premiums Earned, Net	$ 1,585,944	$ 1,531,558	$ 4,673,072	$ 4,496,612
Insurance-Domestic Segment [Member]
Revenue from External Customer [Line Items]
Premiums Earned, Net	1,431,664	1,379,501	4,206,887	4,042,159
Insurance-Domestic Segment [Member] | Other Insurance Liabilities [Member]
Revenue from External Customer [Line Items]
Premiums Earned, Net	465,068	418,133	1,331,143	1,216,411
Insurance-Domestic Segment [Member] | Workers' Compensation [Member]
Revenue from External Customer [Line Items]
Premiums Earned, Net	355,604	347,745	1,047,412	1,010,279
Insurance-Domestic Segment [Member] | Property [Member]
Revenue from External Customer [Line Items]
Premiums Earned, Net	317,498	327,357	977,138	973,606
Insurance-Domestic Segment [Member] | Commercial Automobile [Member]
Revenue from External Customer [Line Items]
Premiums Earned, Net	164,540	170,660	481,249	506,229
Insurance-Domestic Segment [Member] | Products Liability [Member]
Revenue from External Customer [Line Items]
Premiums Earned, Net	128,954	115,606	369,945	335,634
Reinsurance-Global Segment [Member]
Revenue from External Customer [Line Items]
Premiums Earned, Net	154,280	152,057	466,185	454,453
Reinsurance-Global Segment [Member] | Property [Member]
Revenue from External Customer [Line Items]
Premiums Earned, Net	60,523	48,859	175,812	139,991
Reinsurance-Global Segment [Member] | Casualty [Member]
Revenue from External Customer [Line Items]
Premiums Earned, Net	$ 93,757	$ 103,198	$ 290,373	$ 314,462

Subsequent Event Subsequent Eve

Subsequent Event Subsequent Event (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2016
Subsequent Event [Line Items]
pre tax realized gain from sale of wholly owned non insurance business	$ 253.1	$ 135