Accounts Receivable (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Accounts Receivable, Net [Abstract]
Trade customers	$ 923,499	$ 438,538
Allowance for doubtful accounts	(15,322)	(14,095)
Accounts receivable from trade customers, net	908,177	424,443
Federal and state taxes	134,733	60,748
Other	27,591	23,341
Accounts receivable, net	$ 1,070,501	$ 508,532