Revenue - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Income tax expense	$ 4,019	$ 19,761	$ 28,708	$ 54,220
Net sales	(1,870,251)	$ (1,700,843)	(5,340,235)	$ (4,944,294)
Increase in retained earnings	722,274		722,274			$ 619,916
Other current assets	26,692		26,692			$ 34,227
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Income tax expense	277
Net sales	(1,598)		(3,294)
Increase in retained earnings	586		586		$ 798
Other current assets	$ (277)		$ (277)