Receivables (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Schedule of Receivables
Accounts receivables	$ 28,701	$ 33,701
Less: allowance for doubtful accounts	(458)	(1,299)
Total receivables, net	28,243	32,402
Trade accounts receivables [Member]
Schedule of Receivables
Accounts receivables	28,414	33,171
Other receivables [Member]
Schedule of Receivables
Accounts receivables	$ 287	$ 530