Debt (Long Term Debt) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	$ 1,477,661	$ 1,590,655
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums	(2,831)	(3,616)
Less: Short-term borrowings and current portion of long-term debt	(35,192)	(76,770)
Long-term debt (including related party)	1,439,638	1,510,269
$200 million revolving credit facility, LIBOR plus 1.25%-1.75%, due December 2019 (1) | Revolving Credit Facility [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	0	100,000
6.625% Senior notes, due June 2021, $75 million related party | Senior notes (Level 1)
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	400,000	400,000
6.375% Senior notes, due October 2022 | Senior notes (Level 1)
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	524,971	525,000
KOREA, REPUBLIC OF | $100 million revolving credit facility, foreign currency funding-linked base rate plus 1.60%, due June 2017 (2) | Revolving Credit Facility [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	0	40,000
KOREA, REPUBLIC OF | Term loan, LIBOR plus 2.60%, due May 2018 | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	120,000	120,000
KOREA, REPUBLIC OF | Term loan, LIBOR plus 2.70%, due December 2019 | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	55,000	70,000
KOREA, REPUBLIC OF | Term loan, foreign currency funding-linked base rate plus 1.32%, due May 2020 | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	150,000	150,000
KOREA, REPUBLIC OF | Term loan, foreign currency funding-linked base rate plus 1.33%, due May 2020 | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	80,000	80,000
KOREA, REPUBLIC OF | Term loan, fund floating rate plus 1.60%, due June 2020 (3) | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	86,000	40,000
TAIWAN, PROVINCE OF CHINA | Revolving credit facility, TAIFX plus a bank-determined spread, due November 2020 (Taiwan) (5) | Revolving Credit Facility [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	20,000	10,000
JAPAN | Short-term term loans, variable rate (4) | Revolving Credit Facility [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	22,230	15,582
JAPAN | Term loans, fixed rate at 0.53%, due April 2018 | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	19,460	31,465
JAPAN | Short-term term loans, fixed rate at 0.50% | Revolving Credit Facility [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	0	5,808
JAPAN | Term loans, TIBOR plus 1.00% | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	0	2,800
CHINA | Term Loan, LIBOR plus 1.80% due December 2019 [Member] | Loans Payable [Member]
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	$ 0	$ 0