Consolidated Statements of Comprehensive Income (Loss) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Statement of Income and Comprehensive Income [Abstract]
Net income before noncontrolling interests	$ 394,733	$ 449,566	$ 309,080
Other comprehensive income (loss):
Change in unrealized foreign exchange gains (losses)	(18,751)	(2,117)	32,104
Unrealized holding gains on investment securities arising during the period, net of taxes	177,264	152,235	336,757
Reclassification adjustment for net investment gains (losses) included in net income, net of taxes	(81,647)	(36,874)	24,874
Change in unrecognized pension obligation, net of taxes	1,367	120	(1,548)
Other comprehensive income	78,233	113,364	392,187
Comprehensive income	472,966	562,930	701,267
Comprehensive income (loss) to the noncontrolling interest	125	(287)	(44)
Comprehensive income to common shareholders	$ 473,091	$ 562,643	$ 701,223