Consolidated Statements of Stockholders' Equity (USD $) In Thousands	Total	Common Stock [Member]	Additional Paid In Capital [Member]	Retained Earnings [Member]	Unrealized Investment Gains (Losses) [Member]	Currency Translation Adjustments [Member]	Net Pension Asset [Member]	Treasury Stock [Member]	Noncontrolling Interests [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning of period at Dec. 31, 2008		$ 47,024	$ 920,241	$ 3,514,531	$ (142,216)	$ (72,475)	$ (14,268)	$ (1,206,518)	$ 5,361
Stock options exercised and restricted units issued, net of tax			(17,665)
Restricted stock units expensed			23,649
Stock exercised/vested			12					27,322
Stock issued to directors			122					630
Net income to common stockholders	309,080			309,057
Dividends				(38,401)
Unrealized gains on securities not other-than-temporarily impaired					365,136
Unrealized gains (losses) on other-than-temporarily impaired securities					(3,526)
Net change in period	32,104					32,104
Net change in period	(1,548)						(1,548)
Stock repurchased								(147,144)
Change in subsidiary shares									474
Net (income) loss	23								23
Other comprehensive income (loss) , net of tax	392,187								21
End of period at Dec. 31, 2009		47,024	926,359	3,785,187	219,394	(40,371)	(15,816)	(1,325,710)	5,879	163,207
Stock options exercised and restricted units issued, net of tax			(17,042)
Restricted stock units expensed			25,584
Stock exercised/vested			0					45,687
Stock issued to directors			198					536
Net income to common stockholders	449,566			449,287
Dividends				(39,790)
Unrealized gains on securities not other-than-temporarily impaired					114,468
Unrealized gains (losses) on other-than-temporarily impaired securities					885
Net change in period	(2,117)					(2,117)
Net change in period	120						120
Stock repurchased								(471,007)
Change in subsidiary shares									814
Net (income) loss	279								279
Other comprehensive income (loss) , net of tax	113,364								8
End of period at Dec. 31, 2010	3,709,856	47,024	935,099	4,194,684	334,747	(42,488)	(15,696)	(1,750,494)	6,980	276,563
Stock options exercised and restricted units issued, net of tax			(20,601)
Restricted stock units expensed			26,303
Stock exercised/vested			0					56,303
Stock issued to directors			308					564
Net income to common stockholders	394,733			394,803
Dividends				(43,255)
Unrealized gains on securities not other-than-temporarily impaired					98,015
Unrealized gains (losses) on other-than-temporarily impaired securities					(2,343)
Net change in period	(18,751)					(18,751)
Net change in period	1,367						1,367
Stock repurchased								(187,163)
Change in subsidiary shares									671
Net (income) loss	(70)								(70)
Other comprehensive income (loss) , net of tax	78,233								(55)
End of period at Dec. 31, 2011	$ 4,015,952	$ 47,024	$ 941,109	$ 4,546,232	$ 430,419	$ (61,239)	$ (14,329)	$ (1,880,790)	$ 7,526	$ 354,851