Segment Information - Eliminations Footnote (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Operating income (loss)
Operating income (loss)	$ 334,566	$ 131,965
Gross profit	472,154	236,036
Assets elimination
Accounts receivable	883,147		$ 729,784
Other	30,233		29,514
Total assets	6,704,035		$ 6,423,732
Eliminations
Operating income (loss)
Operating income (loss)	(1,571)	$ (3,163)
Assets elimination
Accounts receivable	(109,500)
Elimination of intra-company debt	(15,100)
Other	(14,200)
Total assets	$ (138,844)