Segment Information - Eliminations Footnote (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Operating income (loss)
Gross profit	$ 380,383	$ 171,743	$ 616,419	$ 358,785
Assets elimination
Accounts receivable	794,003		794,003		$ 613,605
Other	33,624		33,624		36,501
Total assets	6,629,676	6,826,763	6,629,676	6,826,763	$ 6,202,082
Eliminations
Operating income (loss)
Gross profit	(6,000)	(4,400)	(9,100)	(600)
Assets elimination
Accounts receivable	(103,100)	(117,100)	(103,100)	(117,100)
Elimination of intra-company debt	(6,300)	(6,600)	(6,300)	(6,600)
Other	(12,600)	(9,000)	(12,600)	(9,000)
Total assets	$ (121,970)	$ (132,679)	$ (121,970)	$ (132,679)