Deferred Grants (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011
Schedule of deferred grants
Property grants	$ 7,975	$ 8,210
Employee grants	1,132	1,123
Total deferred grants	9,107	9,333
Less: Property grants - short-term
Less: Employee grants - short-term	(794)	(770)
Total long-term deferred grants	$ 8,313	$ 8,563