Accounts Receivable Factoring (Details Textual) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Accounts Receivable Factoring (Textual) [Abstract]
Amount outstanding under receivable transfer agreements without recourse	$ 68,564	$ 62,083	$ 68,564	$ 62,083
Amount outstanding under receivable transfer agreements with recourse	11,296	14,040	11,296	14,040
Total amount of accounts receivable without recourse			256,033	149,715
Total amount of accounts receivable with recourse			61,631	38,026
Loss on the sale of receivables	421	408	1,722	1,082
Loss on sale of receivables with recourse	$ 68	$ 50	$ 275	$ 89