Segment Information Segment Information - Net Sales by Destination of Product Delivery (Details) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2017	Jun. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 907,548		$ 872,940		$ 2,758,492	$ 2,544,094
Net sales related to the U.S.
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales		$ 238,342		$ 223,750	703,272	654,235
Net sales attributed to all foreign countries
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales		$ 669,206		$ 649,190	$ 2,055,220	$ 1,889,859