Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Mar. 31, 2011	Jun. 30, 2012
Statement of Income and Comprehensive Income [Abstract]
Net income before noncontrolling interests	$ 108,904	$ 82,120	$ 197,715	$ 244,136
Other comprehensive income (loss):
Change in unrealized foreign exchange gains (losses)	(17,257)	(1,007)	9,853	(1,674)
Unrealized holding gains (losses) on investment securities arising during the period, net of taxes	55,385	92,271	86,054	108,491
Reclassification adjustment for net investment losses included in net income, net of taxes	(15,850)	(14,336)	(33,126)	(46,932)
Change in unrecognized pension obligation, net of taxes	823	707	1,411	1,647
Other comprehensive income (loss)	23,101	77,635	64,192	61,532
Comprehensive income	132,005	159,755	261,907	305,668
Comprehensive income to the noncontrolling interests	(71)	(4)	47	(8)
Comprehensive income to common stockholders	$ 131,934	$ 159,751	$ 261,954	$ 305,660