Long-Term Investments (Details 2) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Roll forward of credit loss recognized in earnings on available-for-sale auction rate securities
Balance at the beginning of the period	$ 308	$ 610
Reductions for securities sold during the period		(366)
Subsequent loss recovery	(4)
Reductions in the amount related to credit (gain) loss for which other-than-temporary impairment was not previously recognized		(1)
Balance at the end of the period	$ 304	$ 243