Bank Credit Agreements and Other Short-Term and Long-Term Debt - Schedule of Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Total long-term debt	$ 215,191	$ 270,083
Current portion of long-term debt	(27,613)	(20,636)
Less: Unamortized debt issuance costs	(1,435)	(1,955)
Long-term debt, net of current portion	186,143	247,492
Notes Payable to Bank | Taiwan Bank
Debt Instrument [Line Items]
Total long-term debt	4,442	1,271
Notes Payable to Bank | Yuan Ta Bank
Debt Instrument [Line Items]
Total long-term debt	749
Term Loan and Revolver
Debt Instrument [Line Items]
Total long-term debt	$ 210,000	$ 268,812