Revenue - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Income tax expense	$ 8,115	$ 11,996
Increase in retained earnings	635,933		$ 619,916
Other current assets	22,820		$ 34,227
Net sales	1,637,652	$ 1,530,571
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	276
Increase in retained earnings	798
Other current assets	(276)
Net sales	$ 311