Consolidated Balance Sheet Consolidated Balance Sheet - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Assets [Abstract]
Fixed maturity securities	$ 12,954,922	$ 12,444,394
Loans receivable	286,652	150,866
Equity securities available for sale	496,522	376,697
Investment funds	1,205,133	1,170,040
Loans receivable	142,858	273,103
Real estate	1,024,102	936,367
Total investments	16,110,189	15,351,467
Cash and cash equivalents	948,710	763,631
Premiums and fees receivable	1,843,386	1,669,186
Due from reinsurers	1,602,750	1,532,829
Prepaid reinsurance premiums	450,199	394,387
Trading account receivables from brokers and clearing organizations	349,223	383,115
Deferred policy acquisition costs	563,842	513,128
Property, furniture and equipment	346,024	348,224
Federal and foreign income taxes	0	48,952
Goodwill	154,327	153,291
Accrued investment income	127,027	123,164
Other assets	530,186	442,782
Total assets	23,025,863	21,724,156
Liabilities:
Reserves for losses and loss expenses	10,897,876	10,669,150
Unearned premiums	3,417,068	3,137,133
Due to reinsurers	246,490	224,752
Trading account securities sold but not yet purchased	120,663	37,035
Deferred Tax Liabilities, Net, Current	40,162	0
Other liabilities	828,787	837,937
Subordinated debentures	727,242	340,320
Senior notes and other debt	1,808,522	1,844,621
Total liabilities	18,086,810	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, 122,641,527 and 123,307,837 shares, respectively	47,024	47,024
Additional paid-in capital	1,021,614	1,005,455
Retained earnings	6,375,893	6,178,070
Accumulated other comprehensive income (loss)	57,282	(66,698)
Treasury stock, at cost, 112,476,391 and 111,810,081 shares, respectively	2,599,312	2,563,605
Total stockholders’ equity	4,902,501	4,600,246
Noncontrolling interests	36,552	32,962
Total equity	4,939,053	4,633,208
Total liabilities and equity	$ 23,025,863	$ 21,724,156