Receivables (Schedule Of Trade Accounts Receivables Net) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Accounts Receivable, Net, Current [Abstract]
Accounts receivable - trade	$ 369,559	$ 273,297
Allowance for doubtful accounts	(1,526)	(2,372)	(1,044)	(1,307)
Accounts receivable - trade, net	$ 368,033	$ 270,925