Gain (Loss) On Disposition Of Assets, Net (Details) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Gain (Loss) On Disposition Of Assets, Net
(Gain) loss on disposition of assets, net	$ 296	$ (7,645)	$ 2,487	$ (24,588)