Accounts Receivable (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Accounts Receivable [Abstract]
Trade and other accounts receivable	$ 146,348	$ 154,296
Revenue in excess of progress billings	9,799	20,525
Allowance for doubtful accounts	(8,664)	(11,274)
Total Accounts Receivable	$ 147,483	$ 163,547