Debt (Details) ¥ in Billions	1 Months Ended	3 Months Ended	6 Months Ended
	Jul. 31, 2018 JPY (¥)	Jun. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jul. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Nov. 30, 2015 USD ($)	May 31, 2015 USD ($)
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		$ 1,330,482,000	$ 1,330,482,000			$ 1,365,533,000
Less: Unamortized premium and deferred debt costs, net		(890,000)	(890,000)			(1,104,000)
Less: Short-term borrowings and current portion of long-term debt		(115,057,000)	(115,057,000)			(123,848,000)
Long-term debt		1,214,535,000	1,214,535,000			1,240,581,000
Proceeds from revolving credit facilities			0	$ 75,000,000
Letter of Credit
Debt Instrument [Line Items]
Standby letters of credit outstanding		500,000	500,000
Term loan, LIBOR plus 1.80%, due December 2019 (China) | China
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		48,500,000	$ 48,500,000			49,000,000
Term loan, LIBOR plus 1.80%, due December 2019 (China) | China | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)			1.80%
Line of Credit | $200 million revolving credit facility, LIBOR plus 1.25%-1.75%, due December 2019 | Revolving Credit Facility
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		0	$ 0			0
Credit facility, borrowing capacity		200,000,000.0	200,000,000.0
Remaining borrowing capacity		199,500,000	$ 199,500,000
Line of Credit | $200 million revolving credit facility, LIBOR plus 1.25%-1.75%, due December 2019 | Revolving Credit Facility | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)			1.25%
Line of Credit | $200 million revolving credit facility, LIBOR plus 1.25%-1.75%, due December 2019 | Revolving Credit Facility | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)			1.75%
Line of Credit | $75 million revolving credit facility, foreign currency funding-linked base rate plus 1.60%, due September 2019 | Revolving Credit Facility
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)			1.60%
Credit facility, borrowing capacity		$ 75,000,000	$ 75,000,000
Interest rate at period end (as a percent)		4.66%	4.66%
Line of Credit | $75 million revolving credit facility, foreign currency funding-linked base rate plus 1.60%, due September 2019 | Korea | Revolving Credit Facility
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		$ 75,000,000	$ 75,000,000			75,000,000
Basis spread on variable rate (as a percent)			1.60%
Credit facility, borrowing capacity		75,000,000	$ 75,000,000
Line of Credit | Revolving credit facility, TAIFX plus a bank-determined spread, due November 2020 (Taiwan) | Taiwan | Revolving Credit Facility
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		20,000,000	20,000,000			20,000,000
Credit facility, borrowing capacity							$ 39,000,000
Remaining borrowing capacity		$ 19,000,000	$ 19,000,000
Interest rate at period end (as a percent)		3.75%	3.75%
Line of Credit | Senior secured revolving credit facility due July 2023 | Revolving Credit Facility | Subsequent Event
Debt Instrument [Line Items]
Credit facility, borrowing capacity					$ 250,000,000
Line of Credit | Senior secured revolving credit facility due July 2023 | Letter of Credit | Subsequent Event
Debt Instrument [Line Items]
Credit facility, borrowing capacity					$ 15,000,000
Senior Notes | 6.625% Senior notes, due June 2021 (2)
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		$ 200,000,000	$ 200,000,000			200,000,000
Stated interest rate (as a percent)		6.625%	6.625%
Face amount of debt		$ 200,000,000	$ 200,000,000
Senior Notes | 6.625% Senior notes, due June 2021 (2) | Subsequent Event
Debt Instrument [Line Items]
Debt redemption price	100.00%
Senior Notes | 6.375% Senior notes, due October 2022
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		$ 524,971,000	$ 524,971,000			524,971,000
Stated interest rate (as a percent)		6.375%	6.375%
Subsidiary Term Loans | Term loan, LIBOR plus 2.70%, due December 2019 | Korea
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		$ 0	$ 0			55,000,000
Basis spread on variable rate (as a percent)			2.70%
Subsidiary Term Loans | Term loan, foreign currency funding-linked base rate plus 1.32%, due May 2020 | Korea
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		141,000,000	$ 141,000,000			150,000,000
Basis spread on variable rate (as a percent)			1.32%
Subsidiary Term Loans | Term loan, fund floating rate plus 1.60%, due June 2020 | Korea
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		$ 150,000,000	$ 150,000,000			86,000,000
Basis spread on variable rate (as a percent)			1.60%
Credit facility, borrowing capacity								$ 150,000,000
Interest rate at period end (as a percent)		4.27%	4.27%
Proceeds from revolving credit facilities		$ 64,000,000
Subsidiary Term Loans | Short-term term loans, variable rate | Japan
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		7,223,000	$ 7,223,000			30,455,000
Remaining borrowing capacity		9,000,000	$ 9,000,000
Subsidiary Term Loans | Short-term term loans, variable rate | Japan | TIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)			0.15%
Subsidiary Term Loans | Term loans, fixed rate at 0.53%, due April 2018 | Japan
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		$ 0	$ 0			6,744,000
Stated interest rate (as a percent)		0.53%	0.53%
Subsidiary Term Loans | Term loan, fixed rate at 0.86%, due June 2022 | Japan
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		$ 36,114,000	$ 36,114,000			39,933,000
Stated interest rate (as a percent)		0.86%	0.86%
Subsidiary Term Loans | Term loan, fixed rate at 0.60%, due July 2022 | Japan
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		$ 7,674,000	$ 7,674,000			8,430,000
Stated interest rate (as a percent)		0.60%	0.60%
Term Loan | Term loan, fixed rate at 3.70%, due May 2020 | Korea
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		$ 120,000,000	$ 120,000,000			$ 120,000,000
Stated interest rate (as a percent)		3.70%	3.70%
Term Loan | Term loan, fixed at 1.30% due July 2023 | Subsequent Event
Debt Instrument [Line Items]
Stated interest rate (as a percent)	1.297%				1.297%
Face amount of debt	¥ 26.0				$ 200,000,000