Related Party Transactions (Details 1) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Related Party Transaction [Line Items]
Sales	$ 1,113,055	$ 859,612	$ 1,064,244	$ 887,879	$ 1,183,473	$ 909,093	$ 1,187,704	$ 918,225	$ 3,924,790	$ 4,198,495	$ 4,540,071
Gross profit	103,694	$ 77,015	$ 97,042	$ 67,755	99,162	$ 85,190	$ 108,173	$ 83,313	345,506	375,838	397,139
Net income (loss)									14,470	(11,322)	122,645
Current assets	1,058,126				1,129,522				1,058,126	1,129,522
Current liabilities	799,776				888,037				799,776	888,037
Noncontrolling interests	790,697				783,739				790,697	783,739	824,049	$ 724,421
Subsidiaries
Related Party Transaction [Line Items]
Sales									6,579,413	6,868,257	8,152,313
Gross profit									188,350	250,847	396,774
Income from continuing operations									12,288	85,220	233,831
Net income (loss)									6,445	81,368	219,431
Current assets	898,081				1,236,171				898,081	1,236,171	1,482,110
Non-current assets	565,416				500,637				565,416	500,637	558,138
Current liabilities	665,387				796,816				665,387	796,816	1,153,101
Non-current liabilities	359,816				342,075				359,816	342,075	381,646
Noncontrolling interests	$ 3,628				$ 11,716				$ 3,628	$ 11,716	$ 13,953