Related Party Transactions (Details) - Unconsolidated Affiliates - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Related Party Transaction [Line Items]
Sales to unconsolidated affiliates	$ 4,605	$ 7,189
Purchases from unconsolidated affiliates	68,916	$ 40,570
Receivable from related parties	2,184		$ 2,406
Payable to related parties	$ 67,244		$ 55,801

Amount for accounts payable to related parties.

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