Accounts Receivable (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	$ 166,179	$ 168,575
Less: Allowance for doubtful accounts	(3,028)	(2,807)
Accounts receivable, net	163,151	165,768
Accounts receivable - trade
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	133,124	130,486
Accounts receivable - grants
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	17,799	20,753
Accounts receivable - insurance claims
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	$ 15,256	$ 17,336