Pension and Severance Plans Textuals (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Non-current (Pension and severance obligations)	$ 137,115,000		$ 137,115,000		$ 139,379,000
Korean Severance Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accrued severance plan, minimum service period			1 year
Provision for severance benefits	7,300,000	7,200,000	12,800,000	7,600,000
Current (Accrued expenses)	9,468,000		9,468,000		9,516,000
Non-current (Pension and severance obligations)	115,141,000		115,141,000		116,997,000
Total Korean severance obligation	124,609,000		124,609,000		126,513,000
Foreign Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions to pension plans	100,000	100,000	200,000	200,000
Expected employer contribution during remaining part of Year	2,100,000		2,100,000
Japan Subsidiaries [Member]
Defined Benefit Plan Disclosure [Line Items]
Curtailment and settlement losses				$ 1,000,000