Accounts Receivable (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	$ 11,896	$ 10,077
Value added tax refunds due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	9,766	8,051
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	$ 2,130	$ 2,026