Accounts Receivable (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Accounts Receivable, Net [Abstract]
Trade customers	$ 951,555	$ 819,739
Affiliates	9,965	7,982
Allowance for doubtful accounts	(18,856)	(17,991)
Accounts receivable from trade customers, net	942,664	809,730
Federal and state taxes	32,901	90,414
Other	28,401	38,599
Accounts receivable, net	$ 1,003,966	$ 938,743