Accounts Receivable, net (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivables, net	$ 364,817		$ 313,657
Unbilled receivables	105,824		108,713
Taxes Receivable	20,075		6,112
Affiliated	3,921	[1]	4,551	[1]
Other receivables	2,588		6,186
Trade accounts receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivables, net	232,409		188,095
Allowance for doubtful accounts	$ 13,614		$ 1,697

[1] mounts represent expenditures on behalf of non-consolidated affiliates and receivables for aircraft charter income.