Segment Information, Revenue by Segment (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) Segment Market	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Segment Information [Abstract]
Number of markets | Market	50
Number of segments | Segment	7
Revenue by Segment [Abstract]
Revenue	$ 2,679,008	$ 2,279,099	$ 2,207,797
Americas/Pacific [Member]
Revenue by Segment [Abstract]
Revenue	385,034	342,429	298,774
Operating Segment [Member]
Revenue by Segment [Abstract]
Revenue	2,679,008	2,279,099	2,207,797
Operating Segment [Member] | Mainland China [Member]
Revenue by Segment [Abstract]
Revenue	886,472	716,991	610,414
Operating Segment [Member] | South Korea [Member]
Revenue by Segment [Abstract]
Revenue	373,357	361,692	413,696
Operating Segment [Member] | Southeast Asia [Member]
Revenue by Segment [Abstract]
Revenue	316,890	268,631	271,897
Operating Segment [Member] | Japan [Member]
Revenue by Segment [Abstract]
Revenue	254,939	256,085	279,042
Operating Segment [Member] | Hong Kong/Taiwan [Member]
Revenue by Segment [Abstract]
Revenue	185,893	166,696	183,979
Operating Segment [Member] | EMEA [Member]
Revenue by Segment [Abstract]
Revenue	182,394	160,275	147,318
Operating Segment [Member] | Other [Member]
Revenue by Segment [Abstract]
Revenue	$ 94,029	$ 6,300	$ 2,677