Condensed Statement of Comprehensive Income (unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Condensed Statement of Comprehensive Income (unaudited) [Abstract]
Net (loss) income	$ (23,142)	$ 27,003	$ 24,896	$ 106,195
Other comprehensive income (loss), before taxes:
Foreign currency translation adjustments	2,298	(4,367)	1,569	3,362
Unrealized gains on investments:
Unrealized gains (losses) arising during period	120	(345)	410	(136)
Less: reclassification adjustment for gains (losses) included in net income	(17)	15	(10)	(33)
Change in unrealized gains (losses) on investments	137	(360)	420	(103)
Changes in employee benefit related items:
Amortization of transition asset	(13)	(13)	(40)	(40)
Amortization of prior service cost	10	10	30	30
Recognized actuarial loss (gain)	79	(13)	124	7
Other comprehensive income (loss), before taxes	2,511	(4,743)	2,103	3,256
Income tax benefit (expense)	(146)	(156)	26	(417)
Comprehensive (loss) income	$ (20,777)	$ 22,104	$ 27,025	$ 109,034