Consolidated Statements of Comprehensive Income (Loss) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Consolidated Statements of Comprehensive Income (Loss) [Abstract]
Net income (loss)	$ 31,919	$ (28,175)	$ 25,015
Unrealized net gains (losses) on securities:
Unrealized holding net gains (losses) arising during the period	10,148	(4,645)	7,390
Less: reclassification adjustment for net gains (losses) included in net income (loss)	1,273	2,657	5,382
Change in unrealized gains (losses) on investments	8,875	(7,302)	2,008
Foreign currency translation adjustments	217	(230)	441
Other comprehensive income (loss)	9,092	(7,532)	2,449
Comprehensive income (loss)	$ 41,011	$ (35,707)	$ 27,464