Pension and Severance Plans (Details) - Foreign Pension Plans [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 9,024	$ 4,177	$ 25,684	$ 6,605
Interest cost	925	725	2,753	2,251
Expected return on plan assets	(961)	(817)	(2,864)	(2,523)
Amortization of prior service cost	9	8	26	25
Recognized actuarial loss	24	23	71	69
Net periodic pension cost	$ 9,021	$ 4,116	$ 25,670	$ 6,427