Debt (Interest Rates) (Details)	Dec. 31, 2015	Dec. 31, 2014
Term Loan Due May 2018 [Member] | KOREA, REPUBLIC OF | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate at Period End	2.99%	0.00%
Term loan, LIBOR plus 2.70%, due December 2019 | KOREA, REPUBLIC OF | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate at Period End	3.02%	3.93%
Term Loan Due May 2020 $150M [Member] | KOREA, REPUBLIC OF | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate at Period End	3.19%	0.00%
Term Loan Due May 2020 $80M [Member] | KOREA, REPUBLIC OF | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate at Period End	3.19%	0.00%
Term Loan Due June 2020 [Member] | KOREA, REPUBLIC OF | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate at Period End	2.32%	0.00%
Term loan, LIBOR plus 3.70%, due June 2016 | KOREA, REPUBLIC OF | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate at Period End	0.00%	3.96%
Term loan, foreign currency funding-linked base rate plus 2.00%, due March 2017 | KOREA, REPUBLIC OF | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate at Period End	0.00%	3.49%
Term loan, LIBOR plus 3.70%, due July 2017 | KOREA, REPUBLIC OF | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate at Period End	0.00%	3.93%
Term loan, foreign currency funding-linked base rate plus 1.75%, due September 2017 | KOREA, REPUBLIC OF | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate at Period End	0.00%	3.28%
Term Loan Due June and November 2016 [Member] | JAPAN | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate at Period End	1.13%	0.00%
Revolving Credit Facility [Member] | $200 million revolving credit facility, LIBOR plus 1.25%-1.75%, due December 2019 (1) | Line of Credit [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate at Period End	2.13%	0.00%
Revolving Credit Facility [Member] | $41 million revolving credit facility, foreign currency funding-linked base rate plus 2.00%, due June 2016 | KOREA, REPUBLIC OF | Line of Credit [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate at Period End	3.32%	0.00%
Revolving Credit Facility [Member] | Short term revolving credit facility, variable rate [Member] | JAPAN | Line of Credit [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate at Period End	0.46%	0.00%
Revolving Credit Facility [Member] | Revolving credit facility, TAIFX plus a bank-determined spread, due November 2020 (Taiwan) [Member] | TAIWAN, PROVINCE OF CHINA | Line of Credit [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate at Period End	1.66%	0.00%