Pension and Severance Plans (Details) - Foreign Pension Plans [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 8,490	$ 1,209	$ 16,660	$ 2,428
Interest cost	924	760	1,828	1,526
Expected return on plan assets	(956)	(850)	(1,903)	(1,706)
Amortization of prior service cost	8	8	17	17
Recognized actuarial loss	23	25	47	46
Net periodic pension cost	$ 8,489	$ 1,152	$ 16,649	$ 2,311