Inventories (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011
Inventories [Abstract]
Inventories-gross	$ 104,029		$ 110,087
Impaired inventory	(31,370)		(31,360)
Total inventories	72,659		78,727
Inventories included in other assets	(1,426)		(1,426)
Inventories, net	71,233		77,301
Inventory impairment charges	$ 4,297	$ 1,042