Unaudited Consolidated Statements of Comprehensive Income (Loss) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Unaudited Consolidated Statements of Comprehensive Income (Loss) [Abstract]
Net income (loss)	$ 11,687	$ (12,971)	$ 27,243	$ (33,673)
Unrealized net gains (losses) on securities:
Unrealized holding net gains (losses) arising during the period	6,104	(17,042)	9,107	(12,085)
Less: reclassification adjustment for net gains (losses) included in net income (loss)	1,617	(909)	1,220	226
Unrealized net gains (losses) on securities	4,487	(16,133)	7,887	(12,311)
Foreign currency translation adjustments	362	(709)	343	(421)
Other comprehensive income (loss)	4,849	(16,842)	8,230	(12,732)
Comprehensive income (loss)	$ 16,536	$ (29,813)	$ 35,473	$ (46,405)