Foreign Operations - Net Sales to External Customers by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Schedule of Revenues from Geographical Segments [Line Items]
Net sales	$ 193,896	$ 162,523	$ 378,059	$ 327,221
United States
Schedule of Revenues from Geographical Segments [Line Items]
Net sales	106,547	79,294	205,483	159,045
Asia (excluding the PRC)
Schedule of Revenues from Geographical Segments [Line Items]
Net sales	25,468	27,467	49,544	54,867
Europe
Schedule of Revenues from Geographical Segments [Line Items]
Net sales	22,823	20,330	46,122	39,460
People's Republic of China (PRC)
Schedule of Revenues from Geographical Segments [Line Items]
Net sales	20,453	20,627	42,761	40,744
Latin America
Schedule of Revenues from Geographical Segments [Line Items]
Net sales	10,119	6,636	17,906	16,666
Other
Schedule of Revenues from Geographical Segments [Line Items]
Net sales	$ 8,486	$ 8,169	$ 16,243	$ 16,439