Pension and Severance Plans (Korean Severance Plan) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Deferred Compensation Liability, Current and Noncurrent [Roll Forward]
Non-current portion of severance obligation	$ 167,197	$ 152,673
Korean Severance Plan [Member]
Deferred Compensation Liability, Current and Noncurrent [Roll Forward]
Balance at the beginning of year	146,880	145,373	$ 126,762
Provision of severance benefits	21,088	17,593	26,550
Severance payments	(15,021)	(10,160)	(10,402)
(Gain) loss on foreign currency	9,796	5,926	2,463
Balance at the end of year	143,151	146,880	145,373
Payments remaining with the National Pension Fund	(192)	(219)	(241)
Korean Severance Plan [Member]
Deferred Compensation Liability, Current and Noncurrent [Roll Forward]
Pension and Other Postretirement and Postemployment Benefit Plans, Liabilities	142,959	146,661	145,132
Less current portion of accrued severance obligation (Note 12)	14,306	13,226	11,197
Non-current portion of severance obligation	$ 128,653	$ 133,435	$ 133,935