Summary of Significant Accounting Policies - Fair Value of Financial Instruments Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, at Carrying Value	$ 10,380	$ 11,012	$ 6,412	$ 6,435
Restricted Cash, Noncurrent	11,200
Marketable Securities, Restricted, Current	94,500
Marketable Securities, Restricted, Current, Fair Value Disclosure	94,200
Long-term Debt	469,736	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, at Carrying Value	10,380	11,012
Cash and Cash Equivalents, Fair Value Disclosure	10,380	11,012
Restricted Cash	693	1,078
Restricted Cash, Current, Fair Value Disclosure	693	1,078
Restricted Cash, Noncurrent	41,920	0
Restricted Cash, Noncurrent, Fair Value Disclosure	41,920	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities, Restricted, Current	94,511	0
Marketable Securities, Restricted, Current, Fair Value Disclosure	94,209	0
Bangkok Bank Loan [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Lines of Credit, Fair Value Disclosure	16,000	0
Long-term Line of Credit	16,000	0
Equipment Loans [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	31,095	0
Lines of Credit, Fair Value Disclosure	31	0
Interest Rate Cap [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	251	0
Notes Payable to Banks [Member] | Term Loan Facility, Term B Loan [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	450,000	0
Notes Payable, Fair Value Disclosure	449,749	$ 0
Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities, Restricted, Current	59,400
US Treasury Notes Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities, Restricted, Current	$ 35,100