Segment Information, Revenue by Major Market (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) Market	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Segment Information [Abstract]
Number of major markets | Market	4
Number of markets | Market	45
Segment Contribution [Abstract]
Revenue	$ 2,581,934	$ 2,420,416	$ 2,679,008
Major Market [Member] | Mainland China [Member]
Segment Contribution [Abstract]
Revenue	625,538	722,526	886,472
Major Market [Member] | South Korea [Member]
Segment Contribution [Abstract]
Revenue	326,478	329,978	373,357
Major Market [Member] | Japan [Member]
Segment Contribution [Abstract]
Revenue	273,681	260,039	254,939
Major Market [Member] | United States [Member]
Segment Contribution [Abstract]
Revenue	425,155	324,727	311,436
Major Market [Member] | All Others [Member]
Segment Contribution [Abstract]
Revenue	$ 931,082	$ 783,146	$ 852,804