Accounts Receivable (Schedule Of Accounts Receivable) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Accounts Receivable, Net [Abstract]
Trade customers	$ 410,302	$ 388,949
Affiliates	315	258
Allowance for doubtful accounts	(11,741)	(11,172)
Receivables from trade customers and affiliates, net	398,876	378,035
Federal and state taxes	20,820	4,011
Other	8,761	18,113
Accounts receivable, net	$ 428,457	$ 400,159