SEGMENT INFORMATION, Segment Contribution (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Contribution [Abstract]
Operating income	$ 80,675	$ 64,362	$ 222,429	$ 175,363
Other income (expense)	(6,982)	(1,172)	(16,940)	(8,470)
Income before provision for income taxes	73,693	63,190	205,489	166,893
Operating Segment [Member]
Segment Contribution [Abstract]
Operating income	154,867	121,352	438,066	347,618
Operating Segment [Member] | Mainland China [Member]
Segment Contribution [Abstract]
Operating income	71,185	42,375	189,901	130,085
Operating Segment [Member] | Americas/Pacific [Member]
Segment Contribution [Abstract]
Operating income	11,848	14,106	38,088	37,884
Operating Segment [Member] | South Korea [Member]
Segment Contribution [Abstract]
Operating income	24,754	23,713	75,836	70,503
Operating Segment [Member] | Southeast Asia [Member]
Segment Contribution [Abstract]
Operating income	21,204	17,380	58,245	43,763
Operating Segment [Member] | Japan [Member]
Segment Contribution [Abstract]
Operating income	15,162	12,786	41,777	36,134
Operating Segment [Member] | Hong Kong/Taiwan [Member]
Segment Contribution [Abstract]
Operating income	8,100	8,096	23,781	20,945
Operating Segment [Member] | EMEA [Member]
Segment Contribution [Abstract]
Operating income	2,614	2,896	10,438	8,304
Corporate and Other [Member]
Segment Contribution [Abstract]
Operating income	$ (74,192)	$ (56,990)	$ (215,637)	$ (172,255)