Accounts Receivable (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Accounts Receivable, Net [Abstract]
Trade customers	$ 576,735	$ 410,302
Affiliates	631	315
Allowance for doubtful accounts	(13,772)	(11,741)
Receivables from trade customers and affiliates, net	563,594	398,876
Federal and state taxes	5,374	20,820
Other	23,996	8,761
Accounts receivable, net	$ 592,964	$ 428,457