Accounts Receivable (Narrative) (Details) (Trade Accounts Receivable [Member], USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Trade Accounts Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Doubtful Accounts Receivable	$ (1,642)	$ (1,810)